Philips xa g3 DATASHEETS

INTEGRATED CIRCUITS

XA-G3

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

Product specification Supersedes data of 1998 Aug 14 IC25 Data Handbook

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1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

FAMILY DESCRIPTION

The Philips Semiconductors XA (eXtended Architecture) family of 16-bit single-chip microcontrollers is powerful enough to easily handle the requirements of high performance embedded applications, yet inexpensive enough to compete in the market for high-volume, low-cost applications.

The XA family provides an upward compatibility path for 80C51 users who need higher performance and 64k or more of program memory. Existing 80C51 code can also easily be translated to run on XA microcontrollers.

The performance of the XA architecture supports the comprehensive bit-oriented operations of the 80C51 while incorporating support for multi-tasking operating systems and high-level languages such as C. The speed of the XA architecture, at 10 to 100 times that of the 80C51, gives designers an easy path to truly high performance embedded control.

The XA architecture supports:

•Upward compatibility with the 80C51 architecture

•16-bit fully static CPU with a 24-bit program and data address

range

•Eight 16-bit CPU registers each capable of performing all

arithmetic and logic operations as well as acting as memory pointers. Operations may also be performed directly to memory.

•Both 8-bit and 16-bit CPU registers, each capable of performing

all arithmetic and logic operations.

•An enhanced instruction set that includes bit intensive logic

operations and fast signed or unsigned 16 × 16 multiply and 32 / 16 divide

XA-G3

•Instruction set tailored for high level language support

•Multi-tasking and real-time executives that include up to 32

vectored interrupts, 16 software traps, segmented data memory, and banked registers to support context switching

•Low power operation, which is intrinsic to the XA architecture,

includes power-down and idle modes.

More detailed information on the core is available in the XA User Guide.

SPECIFIC FEATURES OF THE XA-G3

•20-bit address range, 1 megabyte each program and data space.

(Note that the XA architecture supports up to 24 bit addresses.)

•2.7V to 5.5V operation

•32K bytes on-chip EPROM/ROM program memory =

XA-G37/XA-G33

•512 bytes of on-chip data RAM

•Three counter/timers with enhanced features

(equivalent to 80C51 T0, T1, and T2)

•Watchdog timer

•Two enhanced UARTs

•Four 8-bit I/O ports with 4 programmable output configurations

•44-pin PLCC and 44-pin LQFP packages

ORDERING INFORMATION

ROMless ROM EPROM

P51XAG30KB BD P51XAG33KB BD PXAG37KB BD OTP 0 to +70, Plastic Low Profile Quad Flat Pkg. 30 SOT389–1

P51XAG30KB A P51XAG33KB A PXAG37KB A OTP 0 to +70, Plastic Leaded Chip Carrier 30 SOT187–2

P51XAG30KF BD P51XAG33KF BD PXAG37KF BD OTP –40 to +85, Plastic Low Profile Quad Flat Pkg. 30 SOT389–1

P51XAG30KF A P51XAG33KF A PXAG37KF A OTP –40 to +85, Plastic Leaded Chip Carrier 30 SOT187–2

NOTE:

1. OTP = One Time Programmable EPROM. UV = Erasable EPROM.

TEMPERATURE RANGE °C AND PACKAGE

FREQ (MHz)

DRAWING

NUMBER

1999 Apr 07 853-2052 21197

Philips Semiconductors Product specification

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

PIN CONFIGURATIONS 44-Pin PLCC Package

6140

Pin Function

2 P1.0/A0/WRH 3 P1.1/A1 4 P1.2/A2 5 P1.3/A3 6 P1.4/RxD1 7 P1.5/TxD1 8 P1.6/T2

9 P1.7/T2EX 10 RST 11 P3.0/RxD0 12 NC 13 P3.1/TxD0 14 P3.2/INT0 15 P3.3/INT1 16 P3.4/T0 17 P3.5/T1/BUSW 18 P3.6/WR 19 P3.7/RD 20 XTAL2 21 XTAL1 22 V

PLCC

18 28

Pin Function

23 V 24 P2.0/A12D8 25 P2.1/A13D9 26 P2.2/A14D10 27 P2.3/A15D11 28 P2.4/A16D12 29 P2.5/A17D13 30 P2.6/A18D14 31 P2.7/A19D15 32 PSEN 33 ALE/PROG 34 NC 35 EA 36 P0.7/A11D7 37 P0.6/A10D6 38 P0.5/A9D5 39 P0.4/A8D4 40 P0.3/A7D3 41 P0.2/A6D2 42 P0.1/A5D1 43 P0.0/A4D0 44 V

/VPP/WAIT

SU00525

44-Pin LQFP Package

44 34

12 22

Pin Function

1 P1.5/TxD1 2 P1.6/T2 3 P1.7/T2EX 4 RST 5 P3.0/RxD0 6NC 7 P3.1/TxD0 8 P3.2/INT0

9 P3.3/INT1 10 P3.4/T0 11 P3.5/T1/BUSW 12 P3.6/WRL 13 P3.7/RD 14 XTAL2 15 XTAL1 16 V

17 V

18 P2.0/A12D8 19 P2.1/A13D9 20 P2.2/A14D10 21 P2.3/A15D11 22 P2.4/A16/D12

LQFP

Pin Function

23 P2.5/A17D13 24 P2.6/A18D14 25 P2.7/A19D15 26 PSEN 27 ALE/PROG 28 NC 29 EA 30 P0.7/A11D7 31 P0.6/A10D6 32 P0.5/A9D5 33 P0.4/A8D4 34 P0.3/A7D3 35 P0.2/A6D2 36 P0.1/A5D1 37 P0.0/A4D0 38 V 39 V 40 P1.0/A0/WRH 41 P1.1/A1 42 P1.2/A2 43 P1.3/A3 44 P1.4/RxD1

/VPP/WAIT

DD SS

SU00580

XA-G3

LOGIC SYMBOL

* NOT AVAILABLE ON 40-PIN DIP PACKAGE

RxD0

TxD0 INT0

INT1

T1/BUSW

WRL

ALTERNATE FUNCTIONS

RST

EA/WAIT

PSEN

ALE

VDDV

XTAL1

XTAL2

PORT 3

PORT 1PORT 2

PORT 0

ADDRESS AND DATA BUS

T2EX* T2* TXD1

A3 A2 A1 A0/WRH

BUS

ADDRESS

SU00526

1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

BLOCK DIAGRAM

XA CPU Core

Program

Memory

Bus

32K BYTES

ROM/EPROM

512 BYTES

STATIC RAM

PORT 0

Data Bus

XA-G3

SFR BUS

UART0

UART1

PORT 1

PORT 2

PORT 3

TIMER 0 &

TIMER 1

TIMER 2

WATCHDOG

TIMER

SU00527

1999 Apr 07

Philips Semiconductors Product specification

MNEMONIC

TYPE

NAME AND FUNCTION

XA 16-bit microcontroller family

XA-G3

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

PIN DESCRIPTIONS

PIN. NO.

PLCC LQFP

P0.0 – P0.7 43–36 37–30 I/O Port 0: Port 0 is an 8-bit I/O port with a user-configurable output type. Port 0 latches have 1s

P1.0 – P1.7 2–9 40–44,

P2.0 – P2.7 24–31 18–25 I/O Port 2: Port 2 is an 8-bit I/O port with a user-configurable output type. Port 2 latches have 1s

P3.0 – P3.7 11,

RST 10 4 I Reset: A low on this pin resets the microcontroller, causing I/O ports and peripherals to take on

ALE/PROG 33 27 I/O Address Latch Enable/Program Pulse: A high output on the ALE pin signals external circuitry to

1, 22 16 I Ground: 0V reference.

23, 44 17 I Power Supply: This is the power supply voltage for normal, idle, and power down operation.

written to them and are configured in the quasi-bidirectional mode during reset. The operation of port 0 pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on I/O port configuration and the DC Electrical Characteristics for details.

When the external program/data bus is used, Port 0 becomes the multiplexed low data/instruction byte and address lines 4 through 11.

1–3

2 40 O A0/WRH: Address bit 0 of the external address bus when the external data bus is

3 41 O A1: Address bit 1 of the external address bus. 4 42 O A2: Address bit 2 of the external address bus.

5 43 O A3: Address bit 3 of the external address bus. 6 44 I RxD1 (P1.4): Receiver input for serial port 1. 7 1 O TxD1 (P1.5): Transmitter output for serial port 1.

8 2 I/O T2 (P1.6): T imer/counter 2 external count input/clockout. 9 3 I T2EX (P1.7): Timer/counter 2 reload/capture/direction control

13–195,7–13

11 5 I RxD0 (P3.0): Receiver input for serial port 0. 13 7 O TxD0 (P3.1): Transmitter output for serial port 0. 14 8 I INT0 (P3.2): External interrupt 0 input. 15 9 I INT1 (P3.3): External interrupt 1 input. 16 10 I/O T0 (P3.4): Timer 0 external input, or timer 0 overflow output.

17 11 I/O T1/BUSW (P3.5): Timer 1 external input, or timer 1 overflow output. The value on this pin is

18 12 O WRL (P3.6): External data memory low byte write strobe. 19 13 O RD (P3.7): External data memory read strobe.

I/O Port 1: Port 1 is an 8-bit I/O port with a user-configurable output type. Port 1 latches have 1s

written to them and are configured in the quasi-bidirectional mode during reset. The operation of port 1 pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on I/O port configuration and the DC Electrical Characteristics for details.

Port 1 also provides special functions as described below.

configured for an 8 bit width. When the external data bus is configured for a 16 bit width, this pin becomes the high byte write strobe.

written to them and are configured in the quasi-bidirectional mode during reset. The operation of port 2 pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on I/O port configuration and the DC Electrical Characteristics for details.

When the external program/data bus is used in 16-bit mode, Port 2 becomes the multiplexed high data/instruction byte and address lines 12 through 19. When the external program/data bus is used in 8-bit mode, the number of address lines that appear on port 2 is user programmable.

I/O Port 3: Port 3 is an 8-bit I/O port with a user configurable output type. Port 3 latches have 1s

written to them and are configured in the quasi-bidirectional mode during reset. the operation of port 3 pins as inputs and outputs depends upon the port configuration selected. Each port pin is configured independently. Refer to the section on I/O port configuration and the DC Electrical Characteristics for details.

Port 3 also provides various special functions as described below.

latched as the external reset input is released and defines the default external data bus width (BUSW). 0 = 8-bit bus and 1 = 16-bit bus.

their default states, and the processor to begin execution at the address contained in the reset vector. Refer to the section on Reset for details.

latch the address portion of the multiplexed address/data bus. A pulse on ALE occurs only when it is needed in order to process a bus cycle.

1999 Apr 07

Philips Semiconductors Product specification

SFR

NAME

DESCRIPTION

SFR

XA 16-bit microcontroller family

XA-G3

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

MNEMONIC NAME AND FUNCTIONTYPE

PSEN 32 26 O Program Store Enable: The read strobe for external program memory. When the microcontroller

EA/WAIT/

XTAL1 21 15 I Crystal 1: Input to the inverting amplifier used in the oscillator circuit and input to the internal clock

XTAL2 20 14 O Crystal 2: Output from the oscillator amplifier.

SPECIAL FUNCTION REGISTERS

PIN. NO.

LQFPPLCC

accesses external program memory, PSEN is only active when external code accesses are performed.

35 29 I External Access/Wait: The EA input determines whether the internal program memory of the

microcontroller is used for code execution. The value on the EA pin is latched as the external reset input is released and applies during later execution. When latched as a 0, external program memory is used exclusively, when latched as a 1, internal program memory will be used up to its limit, and external program memory used above that point. After reset is released, this pin takes on the function of bus Wait input. If Wait is asserted high during any external bus access, that cycle will be extended until Wait is released. During EPROM programming, this pin is also the programming supply voltage input.

generator circuits.

BIT FUNCTIONS AND ADDRESSES

ADDRESS

MSB LSB

is driven low in order to enable memory devices. PSEN

RESET VALUE

BCR Bus configuration register 46A — — — WAITD BUSD BC2 BC1 BC0 Note 1 BTRH Bus timing register high byte 469 DW1 DW0 DWA1 DWA0 DR1 DR0 DRA1 DRA0 FF BTRL Bus timing register low byte 468 WM1 WM0 ALEW — CR1 CR0 CRA1 CRA0 EF

CS Code segment 443 00 DS Data segment 441 00 ES Extra segment 442 00

33F 33E 33D 33C 33B 33A 339 338

IEH* Interrupt enable high byte 427 — — — — ETI1 ERI1 ETI0 ERI0 00

337 336 335 334 333 332 331 330

IEL* Interrupt enable low byte 426 EA — — ET2 ET1 EX1 ET0 EX0 00

IPA0 Interrupt priority 0 4A0 — PT0 — PX0 00 IPA1 Interrupt priority 1 4A1 — PT1 — PX1 00 IPA2 Interrupt priority 2 4A2 — — — PT2 00 IPA4 Interrupt priority 4 4A4 — PTI0 — PRI0 00 IPA5 Interrupt priority 5 4A5 — PTI1 — PRI1 00

387 386 385 384 383 382 381 380

P0* Port 0 430 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0 FF

38F 38E 38D 38C 38B 38A 389 388

P1* Port 1 431 T2EX T2 TxD1 RxD1 A3 A2 A1 WRH FF

397 396 395 394 393 392 391 390

P2* Port 2 432 P2.7 P2.6 P2.5 P2.4 P2.3 P2.2 P2.1 P2.0 FF

1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

XA-G3

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

SFR

NAME

P3* Port 3 433 RD WR T1 T0 INT1 INT0 TxD0 RxD0 FF

P0CFGA Port 0 configuration A 470 Note 5 P1CFGA Port 1 configuration A 471 Note 5 P2CFGA Port 2 configuration A 472 Note 5 P3CFGA Port 3 configuration A 473 Note 5 P0CFGB Port 0 configuration B 4F0 Note 5 P1CFGB Port 1 configuration B 4F1 Note 5 P2CFGB Port 2 configuration B 4F2 Note 5 P3CFGB Port 3 configuration B 4F3 Note 5

PCON* Power control register 404 — — — — — — PD IDL 00

PSWH* Program status word (high byte) 401 SM TM RS1 RS0 IM3 IM2 IM1 IM0 Note 2

PSWL* Program status word (low byte) 400 C AC — — — V N Z Note 2

PSW51* 80C51 compatible PSW 402 C AC F0 RS1 RS0 V F1 P Note 3

DESCRIPTION

SFR

ADDRESS

39F 39E 39D 39C 39B 39A 399 398

227 226 225 224 223 222 221 220

20F 20E 20D 20C 20B 20A 209 208

207 206 205 204 203 202 201 200

217 216 215 214 213 212 211 210

BIT FUNCTIONS AND ADDRESSES

RESET

RESET VALUE

VALUE

LSBMSB

RTH0 Timer 0 extended reload,

high byte

RTH1 Timer 1 extended reload,

high byte RTL0 Timer 0 extended reload, low byte 454 00 RTL1 Timer 1 extended reload, low byte 456 00

S0CON* Serial port 0 control register 420 SM0_0 SM1_0 SM2_0 REN_0 TB8_0 RB8_0 TI_0 RI_0 00

S0STAT* Serial port 0 extended status 421 — — — — FE0 BR0 OE0 S0BUF Serial port 0 buffer register 460 x

S0ADDR Serial port 0 address register 461 00 S0ADEN Serial port 0 address enable

S1CON* Serial port 1 control register 424 SM0_1 SM1_1 SM2_1 REN_1 TB8_1 RB8_1 TI_1 RI_1 00

S1STAT* Serial port 1 extended status 425 — — — — FE1 BR1 OE1 S1BUF Serial port 1 buffer register 464 x

S1ADDR Serial port 1 address register 465 00 S1ADEN Serial port 1 address enable

SCR System configuration register 440 — — — — PT1 PT0 CM PZ 00

SSEL* Segment selection register 403 SWE Software Interrupt Enable 47A — SWE7 SWE6 SWE5 SWE4 SWE3 SWE2 SWE1 00

455 00

457 00

307 306 305 304 303 302 301 300

30F 30E 30D 30C 30B 30A 309 308

STINT0

462 00

327 326 325 324 323 322 321 320

32F 32E 32D 32C 32B 32A 329 328

STINT1

466 00

21F 21E 21D 21C 21B 21A 219 218

ESWEN

R6SEG R5SEG R4SEG R3SEG R2SEG R1SEG R0SEG

1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

XA-G3

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

SFR

NAME

SWR* Software Interrupt Request 42A — SWR7 SWR6 SWR5 SWR4 SWR3 SWR2 SWR1 00

T2CON* Timer 2 control register 418 TF2 EXF2 RCLK0 TCLK0

T2MOD* Timer 2 mode control 419 — — RCLK1 TCLK1 — — T2OE DCEN 00 TH2 Timer 2 high byte 459 00

TL2 T imer 2 low byte 458 00 T2CAPH Timer 2 capture register,

T2CAPL Timer 2 capture register,

TCON* Timer 0 and 1 control register 410 TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 00 TH0 Timer 0 high byte 451 00

TH1 Timer 1 high byte 453 00 TL0 T imer 0 low byte 450 00 TL1 T imer 1 low byte 452 00

TMOD Timer 0 and 1 mode control 45C GATE C/T M1 M0 GATE C/T M1 M0 00

TSTAT* Timer 0 and 1 extended status 411 — — — — — T1OE — T0OE 00

WDCON*

WDL Watchdog timer reload 45F 00

WFEED1 WFEED2

NOTES:

* SFRs are bit addressable.

1. At reset, the BCR register is loaded with the binary value 0000 0a11, where “a” is the value on the BUSW pin. This defaults the address bus size to 20 bits since the XA-G3 has only 20 address lines.

2. SFR is loaded from the reset vector.

3. All bits except F1, F0, and P are loaded from the reset vector. Those bits are all 0.

4. Unimplemented bits in SFRs are X (unknown) at all times. Ones should not be written to these bits since they may be used for other purposes in future XA derivatives. The reset value shown for these bits is 0.

5. Port configurations default to quasi-bidirectional when the XA begins execution from internal code memory after reset, based on the condition found on the EA pin. Thus all PnCFGA registers will contain FF and PnCFGB registers will contain 00. When the XA begins execution using external code memory, the default configuration for pins that are associated with the external bus will be push-pull. The PnCFGA and PnCFGB register contents will reflect this difference.

6. The WDCON reset value is E6 for a Watchdog reset, E4 for all other reset causes.

7. The XA-G3 implements an 8-bit SFR bus, as stated in Chapter 8 of the write 16 bits to an SFR will actually write only the lower 8 bits. Sixteen bit SFR reads will return undefined data in the upper byte.

DESCRIPTION

high byte

low byte

Watchdog control register 41F PRE2 PRE1 PRE0 — —

Watchdog feed 1 45D x Watchdog feed 2 45E x

SFR

ADDRESS

357 356 355 354 353 352 351 350

2C7 2C6 2C5 2C4 2C3 2C2 2C1 2C0

2CF 2CE 2CD 2CC 2CB 2CA 2C9 2C8

45B 00

45A 00

287 286 285 284 283 282 281 280

28F 28E 28D 28C 28B 28A 289 288

2FF 2FE 2FD 2FC 2FB 2FA 2F9 2F8

BIT FUNCTIONS AND ADDRESSES

EXEN2

XA User Guide

. All SFR accesses must be 8-bit operations. Attempts to

TR2 C/T2

WDRUN WDTOF

CP/RL2

RESET

RESET VALUE

VALUE

LSBMSB

—

Note 6

1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

XA-G3 TIMER/COUNTERS

The XA has two standard 16-bit enhanced Timer/Counters: Timer 0 and Timer 1. Additionally, it has a third 16-bit Up/Down timer/counter, T2. A central timing generator in the XA core provides the time-base for all XA Timers and Counters. The timer/event counters can perform the following functions:

– Measure time intervals and pulse duration – Count external events – Generate interrupt requests – Generate PWM or timed output waveforms

All of the timer/counters (Timer 0, Timer 1 and Timer 2) can be independently programmed to operate either as timers or event counters via the C/T bit in the TnCON register. All timers count up unless otherwise stated. These timers may be dynamically read during program execution.

The base clock rate of all of the timers is user programmable. This applies to timers T0, T1, and T2 when running in timer mode (as opposed to counter mode), and the watchdog timer. The clock driving the timers is called TCLK and is determined by the setting of two bits (PT1, PT0) in the System Configuration Register (SCR). The frequency of TCLK may be selected to be the oscillator input divided by 4 (Osc/4), the oscillator input divided by 16 (Osc/16), or the oscillator input divided by 64 (Osc/64). This gives a range of possibilities for the XA timer functions, including baud rate

XA-G3

generation, Timer 2 capture. Note that this single rate setting applies to all of the timers.

When timers T0, T1, or T2 are used in the counter mode, the register will increment whenever a falling edge (high to low transition) is detected on the external input pin corresponding to the timer clock. These inputs are sampled once every 2 oscillator cycles, so it can take as many as 4 oscillator cycles to detect a transition. Thus the maximum count rate that can be supported is Osc/4. The duty cycle of the timer clock inputs is not important, but any high or low state on the timer clock input pins must be present for 2 oscillator cycles before it is guaranteed to be “seen” by the timer logic.

Timer 0 and Timer 1

The “Timer” or “Counter” function is selected by control bits C/T in the special function register TMOD. These two Timer/Counters have four operating modes, which are selected by bit-pairs (M1, M0) in the TMOD register. T imer modes 1, 2, and 3 in XA are kept identical to the 80C51 timer modes for code compatibility. Only the mode 0 is replaced in the XA by a more powerful 16-bit auto-reload mode. This will give the XA timers a much larger range when used as time bases.

The recommended M1, M0 settings for the different modes are shown in Figure 2.

SCR Address:440 Not Bit Addressable Reset Value: 00H

PT1 PT0 OPERATING

0 0 Osc/4 0 1 Osc/16 1 0 Osc/64 1 1 Reserved CM Compatibility Mode allows the XA to execute most translated 80C51 code on the XA. The

PZ Page Zero mode forces all program and data addresses to 16-bits only. This saves stack space

TMOD Address:45C Not Bit Addressable Reset Value: 00H

GATE Gating control when set. Timer/Counter “n” is enabled only while “INTn” pin is high and C/T Timer or Counter Selector cleared for Timer operation (input from internal system clock.)

M1 M0 OPERATING

0 0 16-bit auto-reload timer/counter 0 1 16-bit non-auto-reload timer/counter 1 0 8-bit auto-reload timer/counter 1 1 Dual 8-bit timer mode (timer 0 only)

———

Prescaler selection.

XA register file must copy the 80C51 mapping to data memory and mimic the 80C51 indirect addressing scheme.

and speeds up execution but limits memory access to 64k.

Figure 1. System Configuration Register (SCR)

GATE C/T M1

TIMER 1 TIMER 0

“TRn” control bit is set. When cleared Timer “n” is enabled whenever “TRn” control bit is set.

Set for Counter operation (input from “Tn” input pin).

Figure 2. Timer/Counter Mode Control (TMOD) Register

— PT1 PT0 CM PZ

M0 GATE C/T

M1 M0

LSBMSB

SU00589

SU00605

1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

New Enhanced Mode 0

For timers T0 or T1 the 13-bit count mode on the 80C51 (current Mode 0) has been replaced in the XA with a 16-bit auto-reload mode. Four additional 8-bit data registers (two per timer: RTHn and RTLn) are created to hold the auto-reload values. In this mode, the TH overflow will set the TF flag in the TCON register and cause both the TL and TH counters to be loaded from the RTL and RTH registers respectively.

These new SFRs will also be used to hold the TL reload data in the 8-bit auto-reload mode (Mode 2) instead of TH.

The overflow rate for Timer 0 or Timer 1 in Mode 0 may be calculated as follows:

Timer_Rate = Osc / (N * (65536 – Timer_Reload_Value))

where N = the TCLK prescaler value: 4 (default), 16, or 64.

Mode 1

Mode 1 is the 16-bit non-auto reload mode.

Mode 2

Mode 2 configures the Timer register as an 8-bit Counter (TLn) with automatic reload. Overflow from TLn not only sets TFn, but also reloads TLn with the contents of RTLn, which is preset by software. The reload leaves THn unchanged.

XA-G3

Mode 2 operation is the same for Timer/Counter 0. The overflow rate for Timer 0 or Timer 1 in Mode 2 may be

calculated as follows:

Timer_Rate = Osc / (N * (256 – Timer_Reload_Value))

where N = the TCLK prescaler value: 4, 16, or 64.

Mode 3

Timer 1 in Mode 3 simply holds its count. The effect is the same as setting TR1 = 0.

Timer 0 in Mode 3 establishes TL0 and TH0 as two separate counters. TL0 uses the Timer 0 control bits: C/T, GA TE, TR0, INT0, and TF0. TH0 is locked into a timer function and takes over the use of TR1 and TF1 from Timer 1. Thus, TH0 now controls the “Timer 1” interrupt.

Mode 3 is provided for applications requiring an extra 8-bit timer. When Timer 0 is in Mode 3, Timer 1 can be turned on and of f by switching it out of and into its own Mode 3, or can still be used by the serial port as a baud rate generator, or in fact, in any application not requiring an interrupt.

TCON Address:410 Bit Addressable Reset Value: 00H

BIT SYMBOL FUNCTION

TCON.7 TF1 Timer 1 overflow flag. Set by hardware on Timer/Counter overflow.

This flag will not be set if T1OE (TSTAT.2) is set.

Cleared by hardware when processor vectors to interrupt routine, or by clearing the bit in software. TCON.6 TR1 Timer 1 Run control bit. Set/cleared by software to turn Timer/Counter 1 on/off. TCON.5 TF0 Timer 0 overflow flag. Set by hardware on Timer/Counter overflow.

This flag will not be set if T0OE (TSTAT.0) is set.

Cleared by hardware when processor vectors to interrupt routine, or by clearing the bit in software. TCON.4 TR0 Timer 0 Run control bit. Set/cleared by software to turn Timer/Counter 0 on/off. TCON.3 IE1 Interrupt 1 Edge flag. Set by hardware when external interrupt edge detected.

Cleared when interrupt processed. TCON.2 IT1 Interrupt 1 type control bit. Set/cleared by software to specify falling edge/low level triggered

external interrupts. TCON.1 IE0 Interrupt 0 Edge flag. Set by hardware when external interrupt edge detected.

Cleared when interrupt processed. TCON.0 IT0 Interrupt 0 Type control bit. Set/cleared by software to specify falling edge/low level

triggered external interrupts.

Figure 3. Timer/Counter Control (TCON) Register

IE0IT1IE1TR0TF0TR1TF1

LSBMSB

IT0

SU00604C

1999 Apr 07

Philips Semiconductors Product specification

XA 16-bit microcontroller family

32K/512 OTP/ROM/ROMless, watchdog, 2 UARTs

T2CON Address:418 Bit Addressable Reset Value: 00H

BIT SYMBOL FUNCTION

T2CON.7 TF2 Timer 2 overflow flag. Set by hardware on Timer/Counter overflow. Must be cleared by software.

TF2 will not be set when RCLK0, RCLK1, TCLK0, TCLK1 or T2OE=1.

T2CON.6 EXF2 Timer 2 external flag is set when a capture or reload occurs due to a negative transition on T2EX (and

EXEN2 is set). This flag will cause a Timer 2 interrupt when this interrupt is enabled. EXF2 is cleared by

software. T2CON.5 RCLK0 Receive Clock Flag. T2CON.4 TCLK0 Transmit Clock Flag. RCLK0 and TCLK0 are used to select Timer 2 overflow rate as a clock source for

UART0 instead of Timer T1. T2CON.3 EXEN2 Timer 2 external enable bit allows a capture or reload to occur due to a negative transition on T2EX. T2CON.2 TR2 Start=1/Stop=0 control for Timer 2. T2CON.1 C/T2 Timer or counter select.

0=Internal timer

1=External event counter (falling edge triggered) T2CON.0 CP/RL2 Capture/Reload flag.

If CP/RL2 & EXEN2=1 captures will occur on negative transitions of T2EX.

If CP/RL2=0, EXEN2=1 auto reloads occur with either Timer 2 overflows or negative transitions at T2EX.

If RCLK or TCLK=1 the timer is set to auto reload on Timer 2 overflow, this bit has no effect.

Figure 4. Timer/Counter 2 Control (T2CON) Register

C/T2TR2EXEN2TCLK0RCLK0EXF2TF2

LSBMSB

CP/RL2

XA-G3

SU00606A

New Timer-Overflow Toggle Output

In the XA, the timer module now has two outputs, which toggle on overflow from the individual timers. The same device pins that are used for the T0 and T1 count inputs are also used for the new overflow outputs. An SFR bit (TnOE in the TSTAT register) is associated with each counter and indicates whether Port-SFR data or the overflow signal is output to the pin. These outputs could be used in applications for generating variable duty cycle PWM outputs (changing the auto-reload register values). Also variable frequency (Osc/8 to Osc/8,388,608) outputs could be achieved by adjusting the prescaler along with the auto-reload register values. With a

30.0MHz oscillator, this range would be 3.58Hz to 3.75MHz.

Timer T2

Timer 2 in the XA is a 16-bit Timer/Counter which can operate as either a timer or as an event counter. This is selected by C/T2 in the special function register T2CON. Upon timer T2 overflow/underflow, the TF2 flag is set, which may be used to generate an interrupt. It can be operated in one of three operating modes: auto-reload (up or down counting), capture, or as the baud rate generator (for either or both UARTs via SFRs T2MOD and T2CON). These modes are shown in Table 1.

Capture Mode

In the capture mode there are two options which are selected by bit EXEN2 in T2CON. If EXEN2 = 0, then timer 2 is a 16-bit timer or counter, which upon overflowing sets bit TF2, the timer 2 overflow bit. This will cause an interrupt when the timer 2 interrupt is enabled.

If EXEN2 = 1, then Timer 2 still does the above, but with the added feature that a 1-to-0 transition at external input T2EX causes the current value in the Timer 2 registers, TL2 and TH2, to be captured into registers RCAP2L and RCAP2H, respectively. In addition, the transition at T2EX causes bit EXF2 in T2CON to be set. This will cause an interrupt in the same fashion as TF2 when the Timer 2 interrupt is enabled. The capture mode is illustrated in Figure 7.

Auto-Reload Mode (Up or Down Counter)

In the auto-reload mode, the timer registers are loaded with the 16-bit value in T2CAPH and T2CAPL when the count overflows. T2CAPH and T2CAPL are initialized by software. If the EXEN2 bit in T2CON is set, the timer registers will also be reloaded and the EXF2 flag set when a 1-to-0 transition occurs at input T2EX. The auto-reload mode is shown in Figure 8.

In this mode, Timer 2 can be configured to count up or down. This is done by setting or clearing the bit DCEN (Down Counter Enable) in the T2MOD special function register (see Table 1). The T2EX pin then controls the count direction. When T2EX is high, the count is in the up direction, when T2EX is low, the count is in the down direction.

Figure 8 shows Timer 2, which will count up automatically, since DCEN = 0. In this mode there are two options selected by bit EXEN2 in the T2CON register. If EXEN2 = 0, then Timer 2 counts up to FFFFH and sets the TF2 (Overflow Flag) bit upon overflow. This causes the Timer 2 registers to be reloaded with the 16-bit value in T2CAPL and T2CAPH, whose values are preset by software. If EXEN2 = 1, a 16-bit reload can be triggered either by an overflow or by a 1-to-0 transition at input T2EX. This transition also sets the EXF2 bit. If enabled, either TF2 or EXF2 bit can generate the Timer 2 interrupt.

In Figure 9, the DCEN = 1; this enables the Timer 2 to count up or down. In this mode, the logic level of T2EX pin controls the direction of count. When a logic ‘1’ is applied at pin T2EX, the Timer 2 will count up. The Timer 2 will overflow at FFFFH and set the TF2 flag, which can then generate an interrupt if enabled. This timer overflow, also causes the 16-bit value in T2CAPL and T2CAPH to be reloaded into the timer registers TL2 and TH2, respectively.

A logic ‘0’ at pin T2EX causes Timer 2 to count down. When counting down, the timer value is compared to the 16-bit value contained in T2CAPH and T2CAPL. When the value is equal, the

1999 Apr 07

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