ZILOG Z89C0010VSC, Z89C0015VSC Datasheet

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

DC 4083-00 1

ZILOG

FEATURES

P

RELIMINARY PRODUCT SPECIFICATION

■ 16-Bit Single Cycle Instructions

■ Zero Overhead Hardware Looping

■ 16-Bit Data

■ Ready Control for Slow Peripherals

■ Single Cycle Multiply/Accumulate (100 ns)

■ Six-Level Stack

■ 512 Words of On-Chip RAM

■ Static Single-Cycle Operation

■ 16-Bit I/O Port

■ 4K Words of On-Chip Masked ROM

■ Three Vectored Interrupts

■ 64K Words of External Program Address Space

■ Two Conditional Branch Inputs/Two User Outputs

■ 24-Bit ALU, Accumulator and Shifter

■ IBM

®

PC Development Tools

GENERAL DESCRIPTION

The Z89C00 is a second generation, 16-bit, fractional,
two’s complement CMOS Digital Signal Processor (DSP).
Most instructions, including multiply and accumulate,
are accomplished in a single clock cycle. The processor
contains 1 Kbyte of on-chip data RAM (two blocks of
256 16-bit words), 4K words of program ROM and 64K
words of program memory addressing capability. Also,
the processor features a 24-bit ALU, a 16 x 16 multiplier, a
24-bit Accumulator and a shifter. Additionally, the processor
contains a six-level stack, three vectored interrupts and
two inputs for conditional program jumps. Each RAM block
contains a set of three pointers which may be incremented
or decremented automatically to affect hardware looping
without software overhead. The data RAMs can be
simultaneously addressed and loaded to the multiplier for
a true single cycle multiply.

There is a 16-bit address and a 16-bit data bus for external
program memory and data, and a 16-bit I/O bus for
transferring data. Additionally, there are two general
purpose user inputs and two user outputs. Operation with
slow peripherals is accomplished with a ready input pin.
The clock may be stopped to conserve power.

Z89C00

16-BIT DIGITAL
SIGNAL PROCESSOR

Development tools for the IBM PC include a relocatable
assembler, a linker loader, and an ANSI-C compiler. Also,
the development tools include a simulator/debugger, a
cross assembler for the TMS320 family assembly code
and a hardware emulator.

To assist the user in understanding the Z89C00 DSP Q15
two's complement fractional multiplication, an application
note has been included in this product specification as an
appendix.

Notes:

All Signals with a preceding front slash, "/", are active Low, e.g.,
B//W (WORD is active Low); /B/W (BYTE is active Low, only).

Power connections follow conventional descriptions below:

Connection Circuit Device

Power V

CC

V

DD

Ground GND V

SS

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

2 DC 4083-00

ZILOG

GENERAL DESCRIPTION (Continued)

Register

Pointer

0-2

16-Bit Bus

Stack

ACC

24-Bit Bus

ALU

B

A

256 Word

RAM

1

16 x16

Multiplier

24-bit

Instruction

Register

PD

256 Word

RAM

0

Register

Pointer

4-6

PC

16-bit

I/O

Port

PA

MUX

4K
Word
ROM

D-Bus

Status

(5)

Switch

Shifter

24

P-Bus

EXT15-EXT0

Ready

Interrupt

/ROMEN

16

3

UI1-UI0
UO1-UO0

2

2

User
Port

16

16

External Program ROM

16

16

PD15-PD0 PA15-PA0

INT2-INT0
/RESET

S-Bus

Switch

P

Y

X

ER//W, /EI

2

EA2-EA0

3

/RDYE

Figure 1. Functional Block Diagram

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

DC 4083-00 3

ZILOG

789

654321
10
11
12
13
14
15
16
17

18
19
20
21
22
23
24
25
26

68 67 66 65 64 63 62 61

27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44

VSS

PD0
PD1
PD2
PD3

PD4

PD5
PD6
PD7
PD8
PD9

PD10
PD11
PD12
PD13
PD14

PD15

UO1
UO0
INT2
INT1

INT0
UI1

UI0

HALT

/ROMEN
CLK
/RES

/RDYE
ER//W
/EI
EA2
EA1
EA0

Z89C00

PA0

PA1

PA2

PA3

PA4

PA5

PA6

PA7

PA8

PA9

PA10

PA11

VDD

PA12

PA13

PA14

PA15

EXT 15

EXT14

EXT13

EXT12

EXT 11

EXT 10

EXT9

EXT8

EXT7

EXT6

EXT5

EXT4

VSS

EXT3

EXT1

EXT0

EXT2

Figure 2. 68-Pin PLCC Pin Assignments

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

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ZILOG

Table 1. 68-Pin PLCC Pin Identification

No. Symbol Function Direction

1-9 EXT15-EXT7 External data bus Input/Output
10 V

SS

Ground Input
11-26 PD15-PD0 Program data bus Input
27-38 PA11-PA0 Program address bus Output

39 V

DD

Power Supply Input
40-43 PA15-PA12 Program address bus Output
44-46 EA2-EA0 External address bus Output
47 /EI R/W for external bus Output

48 ER//W External bus direction Output
49 /RDYE Data ready Input
50 /RES Reset Input
51 CLK Clock Input

52 /ROMEN Enable ROM Input
53 HALT Stop execution Input
54-55 UI1-UI0 User inputs Input
56-58 INT2-INT1 Interrupts Input

59-60 UO1-UO0 User outputs Output
61-64 EXT3-EXT0 External data bus Input/Output
65 V

SS

Ground Input
66-68 EXT6-EXT4 External data bus Input/Output

PIN FUNCTIONS

CLK

Clock

(input). External clock. The clock may be

stopped to reduce power.

EXT15-EXT0

External Data Bus

(input/output). Data bus
for user defined outside registers such as an ADC or DAC.
The pins are normally in output mode except when the
outside registers are specified as source registers in the
instructions. All the control signals exist to allow a read or
a write through this bus.

ER//W

External Bus Direction

(output, active Low). Data
direction signal for EXT-Bus. Data is available from the
CPU on EXT15-EXT0 when this signal is Low. EXT-Bus is in
input mode (high-impedance) when this signal is High.

EA2-EA0

External Address

(output). User-defined register
address output. One of eight user-defined external registers
is selected by the processor with these address pins for
read or write operations. Since the addresses are part of
the processor memory map, the processor is simply
executing internal reads and writes.

/EI

Enable Input

(output). Write timing signal for EXT-Bus.
Data is read by the external peripheral on the rising edge
of /EI. Data is read by the processor on the rising edge of
CLK, not /EI.

HALT

Halt State

(input). Stop Execution Control. The CPU
continuously executes NOPs and the program counter
remains at the same value when this pin is held High. This
signal must be synchronized with CLK.

INT2-INT0

Three Interrupts

(rising edge triggered). Interrupt
request 2-0. Interrupts are generated on the rising edge of
the input signal. Interrupt vectors for the interrupt service
starting address are stored in the program memory locations
0FFFH for INT0, 0FFEH for INT1 and 0FFDH for INT2.
Priority is: 2 = lowest, 0 = highest.

PA15-PA0

Program memory address bus

(output). For up
to 64K x 16 external program memory. These lines are tri­stated during Reset Low.

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

DC 4083-00 5

ZILOG

/RDYE

Data Ready

(input). User-supplied Data Ready
signal for data to and from external data bus. This pin
stretches the /EI and ER//W lines and maintains data on the
address bus and data bus. The ready signal is sampled
from the rising edge of the clock with appropriate setup
and hold times. The normal write cycle will continue from
the next rising clock only if ready is active.

UI1-UI0

Two Input Pins

(input). General purpose input
pins. These input pins are directly tested by the conditional
branch instructions. These are asynchronous input signals
that have no special clock synchronization requirements.

UO1-UO0

Two Output Pins

(output). General purpose
output pins. These pins reflect the inverted value of status
register bits S5 and S6. These bits may be used to output
data by writing to the status register.

PD15-PD0

Program Memory Data Input

(input). Instruc-

tions or data are read from the address specified by PD15­PD0, through these pins and are executed or stored.

/RES

Reset

(input, active Low). Asynchronous reset signal.
A Low level on this pin generates an internal reset signal.
The /RES signal must be kept Low for at least one clock
cycle. The CPU pushes the contents of the PC onto the
stack and then fetches a new Program Counter (PC) value
from program memory address 0FFCH after the Reset
signal is released. RES Low tri-states the PA and PD bases.

/ROMEN

ROM Enable

(input). An active Low signal enables
the internal ROM. Program execution begins at 0000H
from the ROM. An active High input disables the ROM and
external fetches occur from address 0000H.

Program Memory. Programs of up to 4K words can be
masked into internal ROM. Four locations are dedicated to
the vector address for the three interrupts (0FFDH-0FFFH)
and the starting address following a Reset (0FFCH). Internal
ROM is mapped from 0000H to 0FFFH, and the highest
location for program is 0FFBH. If the /ROMEN pin is held
High, the internal ROM is inactive and the processor
executes external fetches from 0000H to FFFFH. In this
case, locations FFFC-FFFF are used for vector addresses.

Internal Data RAM. The Z89C00 has an internal 512 x
16-bit word data RAM organized as two banks of 256 x
16-bit words each, referred to as RAM0 and RAM1. Each
data RAM bank is addressed by three pointers, referred to
as Pn:0 (n = 0-2) for RAM0 and Pn:1 (n = 0-2) for RAM1. The
RAM addresses for RAM0 and RAM1 are arranged from
0-255 and 256-511, respectively. The address pointers,
which may be written to or read from, are 8-bit registers

connected to the lower byte of the internal 16-bit D-Bus
and are used to perform no overhead looping. Three
addressing modes are available to access the Data RAM:
register indirect, direct addressing, and short form direct.
These modes are discussed in detail later. The contents of
the RAM can be read or written in one machine cycle per
word without disturbing any internal registers or status
other than the RAM address pointer used for each RAM.
The contents of each RAM can be loaded simultaneously
into the X and Y inputs of the multiplier.

Registers. The Z89C00 has 12 internal registers and up to
an additional eight external registers. The external registers
are user definable for peripherals such as A/D or D/A or to
DMA or other addressing peripherals. External registers
are accessed in one machine cycle the same as internal
registers.

ADDRESS SPACE

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

6 DC 4083-00

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FUNCTIONAL DESCRIPTION

General. The Z89C00 is a high-performance Digital Signal

Processor with a modified Harvard-type architecture with
separate program and data memory. The design has been
optimized for processing power and minimizing silicon
space.

Instruction Timing. Many instructions are executed in one
machine cycle. Long immediate instructions and Jump or
Call instructions are executed in two machine cycles.
When the program memory is referenced in internal RAM
indirect mode, it takes three machine cycles. In addition,
one more machine cycle is required if the PC is selected as
the destination of a data transfer instruction. This only
happens in the case of a register indirect branch instruction.

An Acc + P => Acc; a(i) * b(j) → P calculation and
modification of the RAM pointers, is done in one machine
cycle. Both operands, a(i) and b(j), can be located in two
independent RAM (0 and 1) addresses.

Multiply/Accumulate. The multiplier can perform a 16-bit
x 16-bit multiply or multiply accumulate in one machine
cycle using the Accumulator and/or both the X and Y
inputs. The multiplier produces a 32-bit result, however,
only the 24 most significant bits are saved for the next
instruction or accumulation. The multiplier provides a flow
through operation whenever the X or Y register is updated,
an automatic multiply operation is performed and the P
register is updated. For operations on very small numbers
where the least significant bits are important, the data
should first be scaled by eight bits (or the multiplier and
multiplicand by four bits each) to avoid truncation errors.
Note that all inputs to the multiplier should be fractional
two’s complement 16-bit binary numbers. This puts them
in the range [–1 to 0.9999695], and the result is in 24-bits
so that the range is [–1 to 0.9999999]. In addition, if 8000H
is loaded into both X and Y registers, the resulting
multiplication is considered an illegal operation as an
overflow would result. Positive one cannot be represented
in fractional notation, and the multiplier will actually yield
the result 8000H x 8000H = 8000H (–1 x –1 = –1).

ALU. The 24-bit ALU has two input ports, one of which is
connected to the output of the 24-bit Accumulator. The
other input is connected to the 24-bit P-Bus, the upper
16 bits of which are connected to the 16-bit D-Bus. A shifter
between the P-Bus and the ALU input port can shift the
data by three bits right, one bit right, one bit left or no shift.

Hardware Stack. A six-level hardware stack is connected
to the D-Bus to hold subroutine return addresses or data.
The CALL instruction pushes PC+2 onto the stack. The
RET instruction pops the contents of the stack to the PC.

User Inputs. The Z89C00 has two inputs, UI0 and UI1,
which may be used by jump and call instructions. The jump
or call tests one of these pins and if appropriate, jumps to
a new location. Otherwise, the instruction behaves like a
NOP. These inputs are also connected to the status register
bits S10 and S11 which may be read by the appropriate
instruction (Figure 3).

User Outputs. The status register bits S5 and S6 connect
through an inverter to UO0 and UO1 pins and may be
written to by the appropriate instruction.

Interrupts. The Z89C00 has three positive edge triggered
interrupt inputs. An interrupt is acknowledged at the end of
any instruction execution. It takes two machine cycles to
enter an interrupt instruction sequence. The PC is pushed
onto the stack. A RET instruction transfers the contents
of the stack to the PC and decrements the stack pointer
by one word. The priority of the interrupts is 0 = highest,
2 = lowest.

Registers. The Z89C00 has 12 physical internal registers
and up to eight user-defined external registers. The EA2­EA0 determines the address of the external registers. The
/EI, /RDYE, and ER//W signals are used to read or write
from the external registers.

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

DC 4083-00 7

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REGISTERS

There are 12 internal registers which are defined below:

Register Register Definition

P Output of Multiplier, 24-bit, Read Only
X X Multiplier Input, 16-bit
Y Y Multiplier Input, 16-bit

A Accumulator, 24-bit

SR Status Register, 16-bit

Pn:b Six Ram Address Pointers, 8-bit Each

PC Program Counter, 16-bit

The following are virtual registers as physical RAM does
not exist on the chip.

Register Register Definition

EXTn External registers, 16-bit

BUS D-Bus
Dn:b Eight Data Pointers

P holds the result of multiplications and is read only.

X and Y are two 16-bit input registers for the multiplier.

These registers can be utilized as temporary registers
when the multiplier is not being used. The contents of the
P register will change if X or Y is changed.

A is a 24-bit Accumulator. The output of the ALU is sent to
this register. When 16-bit data is transferred into this
register, it goes into the 16 MSB’s and the least significant
eight bits are set to zero. Only the upper 16 bits are
transferred to the destination register when the Accumulator
is selected as a source register in transfer instructions.

Pn:b are the pointer registers for accessing data RAM.
(n = 0,1,2 refer to the pointer number) (b = 0,1 refers to
RAM bank 0 or 1). They can be directly read from or written
to, and can point to locations in data RAM or indirectly to
Program Memory.

EXT(n) are external registers (n = 0 to 7). There are eight
16-bit registers here for accessing External data,
peripherals, or memory. Note that the actual register RAM
does not exist on the chip, but would exist as part of the
external device such as an ADC result latch.

BUS is a read-only register which, when accessed, returns
the contents of the D-Bus.

Dn:b refer to possible locations in RAM that can be used
as a pointer to locations in program memory. The
programmer decides which location to choose from two
bits in the status register and two bits in the operand. Thus,
only the lower 16 possible locations in RAM can be
specified. At any one time there are eight usable pointers,
four per bank, and the four pointers are in consecutive
locations in RAM. For example, if S3/S4 = 01 in the status
register, then D0:0/D1:0/D2:0/D3:0 refer to locations
4/5/6/7 in RAM bank 0. Note that when the data pointers are
being written to, a number is actually being loaded to Data
RAM, so they can be used as a limited method for writing
to RAM.

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

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REGISTERS (Continued)

Figure 3. Status Register

SR is the status register (Figure 3) which contains the ALU

status and certain control bits as shown in the following
table.

Status
Register Bit Function

S15 (N) ALU Negative
S14 (OV) ALU Overflow
S13 (Z) ALU Zero
S12 (L) Carry
S11 (UI1) User Input 1
S10 (UI0) User Input 0

S9 (SH3) MPY Output Shifted Right by Three Bits
S8 (OP) Overflow Protection
S7 (IE) Interrupt Enable
S6 (UO1) User Output 1
S5 (UO0) User Output 0
S4-3 “Short Form Direct” Bits
S2-0 (RPL) RAM Pointer Loop Size

RPL Description

S2 S1 S0 Loop Size

0 0 0 256
001 2
010 4
011 8

100 16
101 32
110 64
1 1 1 128

The status register may always be read in its entirety.
S15-S10 are set/reset by the hardware and can only be
read by software. S9-S0 can be written by software.

S7 S6 S5 S4 S3 S2 S1 S0S15 S14 S13 S12 S11 S10 S9 S8

N OV Z C UI1 UI0 SH3 OP IE UO1 UO0 RPL

"Short Form Direct" bits
User Output 0-1

Interrupt Enable

Overflow protection

MPY output shifted right
by 3 bit with sign extension

User Input 0-1

Carry

Zero
Overflow
Negative

0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1

256
2
4
8
16
32
64
128

Ram Pointer Loop Size

Read

and

Write

Read Only

Z89C00

16-BIT DIGITAL SIGNAL PROCESSOR

PRELIMINARY

DC 4083-00 9

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S15-S12 are set/reset by the ALU after an operation.
S11-S10 are set/reset by the user inputs. S6-S0 are control
bits described elsewhere. S7 enables interrupts. S8, if 0
(reset), allows the hardware to overflow. If S8 is set, the
hardware clamps at maximum positive or negative values
instead of overflowing. If S9 is set and a multiply instruction
is used, the shifter shifts the result three bits right with sign
extension.

PC is the Program Counter. When this register is assigned
as a destination register, one NOP machine cycle is added
automatically to adjust the pipeline timing.

Figure 4. RAM, ROM, and Pointer Architecture

1. Register Indirect

Pn:b n = 0-2, b = 0-1
The most commonly used method is a register indirect
addressing method, where the RAM address is
specified by one of the three RAM address pointers (n)
for each bank (b). Each source/destination field in
Figures 5 and 8 may be used by an indirect instruction
to specify a register pointer and its modification after
execution of the instruction.

RAM Pointers

P0:0

P1:0

P2:0

%37

RAM0

256 x 16-Bit

@P1:0

%0321

%00

RAM1

256 x 16-Bit

%0321

%00

Internal ROM

4K x 16-Bit

%1234

%0000

%1000

%0321@@P1:0

@D0:1

RAM Pointers

P0:1

P1:1

P2:1

D0:0 %0321
D1:0
D2:0
D3:0

D0:1
D1:1
D2:1
D3:1

Data Pointers

%37 %04

S4 / S3 = 01

The following Instructions load
%1234 into the Accumulator:

LD A,@@P1:0
LD A,@D0:1

%FF %FF

D3 D2 D1 D0D8

bn1n0

RAM Pointer Register

Operation

RAM Bank

Figure 5. Indirect Register

RAM ADDRESSING

The address of the RAM is specified in one of three ways (Figure 4):