SGS Thomson Microelectronics TS68HC901 Datasheet



HCMOS MULTI-FUNCTION PERIPHERAL

The TS68HC901 CMFP (CMOS Multi-Function Peripheral) is acombination of many ofthe necessary peripheral functions in a microprocessor system. Includedare :

.8 INPUT/OUTPUTPINS

• Individually programmable direction

• Individual interrupt sourcecapability

Programmable edgeselection

.16 SOURCEINTERRUPT CONTROLLER

• 8 Internalsources

• 8 Externalsources

• Individual source enable

• Individual source masking

• Programmable interrupt servicemodes

Polling

Vector generation

OptionalIn-servicestatus

• Daisy chaining capability

.FOUR TIMERS WITHINDIVIDUALLY

PROGRAMMABLE PRESCALING

• Two multimodetimers Delay mode

Pulse widthmeasurement mode

Event counter mode

• Two delaymode timers

• Independent clock input

• Time outoutput option

.SINGLECHANNEL USART

• Full Duplex

• Asynchronous to65 kbps

• Bytesynchronous to1 Mbps

• Internal/External baud rate generation

• DMA handshake signals

• Modem control

• Loop backmode

.68000 BUSCOMPATIBLE

TS68HC901

PDIP48

PLCC52

(Ordering Information at the end of the Datasheet

DESCRIPTI ON

The use of the CMFP in a system can significantly reduce chip count, thereby reducing system cost. TheCMFPis completely68000bus compatible,and 24 directly addressable internal registers provide thenecessary control andstatus interfacetotheprogrammer.

TheCMFP isa derivative of theMK3801 STI, aZ80 familyperipheral.

September1992

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TS68HC901

INTRODUCTION

The TS68HC901 multi-function peripheral (CMFP) is a member of the 68000 peripherals. The CMFP directly interfaces to the 68000processor via anasynchronous bus structure. Bothvectored and polledinterrupt schemes are supported,withtheCMFP providing unique vectornumber generation for each of its 16 interrupt sources. Additionally, handshake linesareprovided tofacilitate DMAC interfacing. Referto blockdiagram of the TS68HC901.

The TS68HC901 performs many of the functions commonto most microprocessor-based systems.

The resources available to the userinclude:

.EightIndividually Programmable I/OPins withIn-

terrupt Capability

.16-Source Interrupt Controller with Individual

Source Enabling andMasking

.Four Timers, Two of which are Multi-Mode Ti-

mers

Figure 1: TS68HC901 Block Diagram

.Timers may be used as Baud Rate Generators

for the Serial Channel

.Single-Channel Full-Duplex Universal Synchro-

nous / Asynchronous Receiver-Transmitter (USART) thatSupports Asynchronous andwiththe Addition of a Polynomial Generator Checker Supports Byte Synchronous Formats

Byincorporating multiple functions withintheCMFP, the systemdesigner retains flexibility while minimizing device count.

Froma programmer’s pointof view, theversatility of the CMFPmay be attributed to its register set. The registers arewell organized andallowthe CMFP to be easily tailored to a varietyof applications. All of the 24registers arealso directly addressable which simplifies programming. The registermap is shown in Figure2.

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Address

Binary

Hex

RS5 RS4 RS3 RS2 RS1

TS68HC901

Figure 2 : CMFP Register Map.

Abbreviation Register Name

01 03 05

07 09 0B

0F 11 13 15 17

19 1B 1D

29 2B 2D

Note : Hex addresses assume t hat R S1 connects wit h A 1, R S2connects with A2, et c... and t hat DS is connected to LDS on the 68000 or D S i s connec t to DS on th e 68008.

GPIP

AER

DDR

IERA IERB IPRA IPRB ISRA

ISRB IMRA IMRB

TACR TBCR

TCDCR

TADR TBDR TCDR TDDR

SCR UCR RSR

TSR

UDR

General Purpose I/O Register Active Edge Register Data DirectionRegister

Interrupt EnableRegister A Interrupt EnableRegister B Interrupt Pending Register A Interrupt Pending Register B Interrupt In-serviceRegister A Interrupt In-serviceRegister B Interrupt Mask Register A Interrupt Mask Register B Vector Register

Timer A Control Register Timer B Control Register Timers C and D Control Register Timer A Data Register Timer B Data Register Timer C Data Register Timer D Data Register

Synchronous Character Register USART Control Register Receiver Status Register Transmitter StatusRegister USART Data Register

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TS68HC901

Figure 3 : PDIP Pin connection

Figure 4 : PLCC Pin connection

Pin MOTOROLA

6800 Type

MOTOROLA

Multiplexed

INTEL

PIN DESCR IPTIO N

GND : Ground VCC: +5 volts(± 5%) R/W : Read/Write (input). This input defines a

data transfert as a Read (High) or Write (Low) cycle. This signal is used as WR with an Intelprocessortype.

DTACK : This outputsignals the completion ofthe

operation phaseofa buscycleto theprocessor. If the bus cycle is a processor read, the CMFP asserts DTACKto indicate thatthe information ontheData bus is valid.If the buscycle is a processor to the CMFP, DTACK acknowledges the acceptance of the data by the CMFP. DTACKwillbeassertedonlybyanCMFP that has CS or IAK (and IEI) asserted. This signal is not used with a 6800processortype.

48 47

R/W V

CS DS

R/W

CS RD

ALE

CS : Chip Select (input, active low). CS is u-

sed to select theTS68HC901 CMFP for accesses to the internal registers. CS and IACK must not be asserted at the same time.

DS : Data Stobe(input, active low).This Input

is part of the internal chip select and interrupt acknowledge functions. The CMFP mustbe located on thelower portionof the16-bit data-busso thatthe vector number passed to the processor during an interrupt acknowledge cycle willbe located inthe low byte of the data word.Asa result,DS mustbe connected to the processor’s lower data strobe if vectored interrupt are to be used. Note thatthis forces all registers tobe located atodd addresses and latchesdataonthe risingedge forwrites.This signal isused asRD with anIntel processor type.

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TS68HC901

RS1-RS5: (A1-A5)

Register Address Bus (inputs). The address bus is used to address one of the internal registers during a read or write cycle.

D0-D7: Data Bus (bi-directional, tri-stateable).

This bus is usedto receive data from or transmit data totheMFP’sinternal registers duringa processor read orwrite cycle. During an interrupt acknowledge cycle, thedata busisused to pass a vector numberto theprocessor. Since theMFP is an 8-bit peripheral, the MFP could be locatedon either theupper or lowerportion of the 16-bit data bus (even or odd address). However, during an interrupt acknowledge cycle, the vector number passedto theprocessor must belocated in thelow byteof thedata word.As aresult, D0-D7 of the MFPmustbe connected to the low eightbits of theprocessor data bus, placing MFP registers at odd addresses if vectored interrupt are to be used.

CLK : The clock input is a single-phase TTL

compatible signal used for internal timing . This input shouldnot begated off at any time and must conform to minimum and maximum pulse width times. The clock is not necessarily the system clock in frequency nor phase. When the bus is multiplexed (MPX=1), an address strobe signalis connected to this pin. In the nonmultiplexed mode (MPX=0), this input is connected to the system clock when used with a 68000 processor type or to VSS(0VDC) whenused witha 6800 processor type.

RESET : Device reset. (input, active low). Reset

disables the USARTreceiver and transmitter, stops alltimers and forces the timer outputs low, disables all interrupt channels and clears any pending interrupts.The General Purpose Interrupt/I/O lines will be placed in the tri-state input mode.Allinternalregisters(exceptthetimer,USART dataregisters, and transmit status register) willbe cleared.

MPX: This inputselects thedata bus mode:

MPX =0 : non multiplexed mode MPX=1:multiplexed mode.Theregister

select lines RS1-RS5 and the data bus D0 -D7 are mult iplexed. An ad dress strobemustbeconnected totheCLKpin.

IRQ : Interrupt Request (output, active low, o-

pen drain). This output signals the processor that an interrupt is pending from the CMFP.These are 16 interrupt channels that can generate an interrupt request. Clearing the interrupt pendingregisters (IPRA and IPRB) or clearing the inte rr u pt mask regist ers (IMRA and IMRB)willcauseIRQ to be negated. IRQ willalso be negated astheresultof an interrupt acknowledge cycle, unless additional interrupts are pending in t he CMFP. Ref er t o par agraph INTE RRUPTSfor further information.

IACK : Interrupt Acknowledge (input, act ive

low). IACK is used to signal the TS68HC901 that the CPU is acknowledging an interrupt. CS and IACk must not beasserted atthe same time.

IEI : Interrupt Enable In (input, active low). IEI

isusedtosignalthe TS68HC901 that no higher priority device is requesting interrupt service.

IEO : InterruptEnable Out (output, activelow).

IEO is used to signal lower priority peripherals that neitherthe TS68HC901 nor another higher priority peripheral is requesting interrupt service.

I0-I7 : General Purpose Interrupt I/O lines.

Theselines maybe usedas interrupt inputsand/orI/Olines.Whenusedasinterrupt inputs, their activeedge isprogrammable. Adatadirection register isusedto define which lines are to be Hi-Z inputs and which lines are to be push-pull TTL compatible outputs.

SO : SerialOutput.This is theoutputof the U-

SART transmitter.

SI : Serial Input. This is the input to the U-

SART receiver.

RC : Receiver Clock. This input controls the

serialbit rate of the USARTreceiver.

TC : TransmitterClock.Thisinputcontrols the

serialbit rate of the USARTtransmitter.

RR : Receiver Ready. (output, active low)

DMA output for receiver, which reflects the status of Buffer Full in port number

15.

TR : Transmitter Ready. (output, active low)

DMA output for transmitter, which reflects the status of Buffer Empty in port number 16.

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TS68HC901

TAO,TBO, TCO,TDO:

Timer Outputs. Each of the four timers has an output which can produce a square wave. The output will change states each timercycle; thusone fullperiod of thetimer out signal is equal to two timer cycles. TAO or TBO can be reset (logic ”O”)by a writeto TACR,or TBCR respectively.

TAI,TBI: Timer A, B inputs. These inputs are

controlsignals for timers A and B in the pulse width measurement mode and event count mode. These signals generate interrupts at the same priority level asthegeneral purpose I/Ointerrupt lines I4 and I3, respectively. I4 and I3 do not haveinterrupt capability when thetimers areoperated inthepulsewidthmeasure-

XTAL1, XTAL2 :

Timer Clock inputs. A crystal can be connectedbetween XTAL1 and XTAL2, or XTAL1 can bedriven witha TTL level clock.WhendrivingXTAL1with aTTLle-

mentmode orthe event countmode -under these conditions I4 and I3 may only be used for I/O. Refer to paragraph TIMERSfor further information.

velclock,XTAL2 mustbeallowedtofloat. Whenusingacrystal,external capacitors are required. See figure 35. All chip acces s es are independent of t he tim er clock.

SIGNAL SUMMARY.

Signal Name Mnemonic I/O Active

Power Input V Ground GND Input Low Clock CLK Input N/A Chip Select CS Input Low Data Strobe DS Input Low Read/Write R/W Input Read-High / Write-Low Data tranfer Acknowledge DTACK Output Low Register Select Bus RS1-RS5 Input N/A Data Bus D0-D7 I/O N/A Reset RESET Input Low Interrupt Request IRQ Output Low Interrupt Acknowledge IACK Input Low Interrupt Enable In IEI Input Low Interrupt EnableOut IEO Output Low General Purpose I/O - Interrupt Lines I0-I7 I/O N/A Timer Clock XTAL1,XTAL2 Input High Timer Inputs TAI, TBI Input N/A Timer Outputs TAO, TBO, TCO, TDO Output N/A Serial Input SI Input N/A Serial Output SO Output N/A Receiver Clock RC Input N/A Transmitter Clock TC Input N/A Receiver Ready RR Output Low Transmitter Ready TR Output Low MPX MPX Input N/A

Input High

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BUSOPERATION

Thefollowingparagraphs explain the controlsignals and bus operation during data transfer operations andreset.

DATA TRANSFER OPERATIONS. Transfer ofdata between devicesinvolvesthe follo-

wing pins: Register Select Bus - RS5 throughRS1 DataBus - D0 throughD7 ControlSignals The address and databusesareseparate parallel busesused to transfer data using an asynchronous bus structure.In all cycles, thebus master assumes responsibilityfordeskewing allsignals itissuesatboth the start and end of a cycle. Additionally, the bus master is responsible for deskewing the acknowledge and data signalsfrom theperipheral devices.

ReadCycle. To read a CMFP register, CS andDS must be asserted, and R/W must be high. The CMFPwill place the content of the registerwhich is selected by the register select bus (RS1 through RS5) on the data bus(D1 through D7)and then assertDTACK. The register addresses are shownon Figure2. Aftertheprocessor has latchedthedata, DS is negated. The negation of either CSor DS will terminate the read operation. The CMFP will drive DTACKHigh andplace itinthehigh-impedance state. Thetimingfor areadcycleis shown in figure 21.

WriteCycle.To writea register CSand DS must be asserted,and R/W must below. TheCMFP willdecodetheaddress bus todetermine which registeris selected. Then the register will be loaded with the contentsof thedata bus and DTACK will be asserted. When the processor recognizes DTACK, DS will be negated.The write cycle is terminated when either CS or DS is negated. The CMFP will drive DTACKhighandplaceitinthehigh-impedance state. Thetimingfor awritecycleisshown in figure22.

TS68HC901

INTERRUPTACKNOWLEDGE OPERATION. The CMFP has 16 interruptsources, eight internal

and eight external. When an interrupt request is pending,theCMFPwillassertIRQ. In a vectored interruptscheme,the processor willacknowledge the interruptrequestbyperforming aninterrupt acknowledge cycle. IACK and DS will be asserted. The CMFPresponds totheIACKsignalbyplacing avector number on the lower eight bits of the data bus. This vectornumber corresponds tothe IRQhandler for the particular interrupt requesting service. The format ofthis vector number is given in figure6.

Whenthe CMFPasserts DTACKtoindicate that valid data isonthebus, theprocessor willlatchthe data and terminate the bus cycle by negating DS. WheneitherDS orIACKarenegated, theCMFPwill terminate the interrupt acknowledge operation by driving DTACK high and placingit inthe high-impedance state. Also, thedata buswillbe placed in the high-impedance state.IRQ will benegatedas a result of the IACK cycle unless additional interrupts are pending.

The CMFP can be part of a daisy-chain interrupt structurewhich allows multiple CMFPsto be placed at the same interrupt level by sharing a common IACK signal.A daisy-chain priority schemeisimplemented with IEI and IEO signals. IEI indicates that no higherpriority device is requesting interrupt service. IEOsignals lowerpriority devices that neither this devicenor any higher priority devices is requesting service. To daisy-chain CMFPs, the highest priority CMFP has its IEI tied low and successive CMFPs havetheirIEI connected to the next higher priority device’sIEO.Notethatwhenthedaisy-chain

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TS68HC901

interrupt structure is notimplemented, the IEI of all CMFPsmust betied low.

When the processor initiates an interrupt acknowledge cycle by driving IACK and DS, the CMFP whoseIEI is low may respond witha vectornumber if interrupt is pending. If this device doesnot have a pending interrupt, IEO is asserted which allowsthe nextlowerpriority device to respond to the interrupt acknowledge. When an CMFP propagates IEO, it willnot drive thedata bus norDTACK during the interruptacknowledge cycle. The timingfor an IACK cycleis shown in figure 23 and 24.

RESET OPERATION The reset operation will initialize the CMFP to a

known state. Thereset operation requires that the RESET input be asserted for a minimum of two microseconds. During a device reset condition, all internal CMFP registers are cleared except for the timer data registers (TADR, TBDR, TCDR and TDDR), the USART data register (UDR), the transmitterstatus register (TSR) andthe interrupt vector register. Alltimers are stopped and the USART receiver and transmitter are disabled. The interrupt channelsare also disabled and any pending inter-

rupts are cleared. In addition, the general purpose interruptI/Olinesare placed in thehigh-impedance inputmode andthetimeroutputsaredrivenlow. ExternalCMFPsignalsarenegated.The interrupt vector register is initialized to a0Fh.

NON MULTIPLEXED MODE In this mode, theMPX inputmustbe setto zero, and

the TS68HC901 can be used witha 68000 processortype or a6800processor type.Referto figure 21 to 24for the electrical characteristics.

With a6800processor typetheDS pin isconnected to the E signal of the processor, the DTACK signal is not usedand the CLKmust be zeroed.

MULTIPLEXED MODE The CMFPcan beusedeitheron aMOTOROLAor

INTELbus type. Inthiscasethe MPX pinisconnected to Vcc. The table page4 givesthe signification ofthe differentsignals used. Adummyaccessto the TS68HC901 hasto be done beforeany validaccess in orderto set upthe internal logicof sampling.

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TS68HC901

INTERRUPT STRUCTURE

In a 68000 system, the CMFP will be assigned to oneof the sevenpossible interrupt levels.All interrupt service requests from the CMFP’s 16 interrupt channelswillbepresented atthislevel.Although,as an interrupt controller, the CMFP will internally prioritize its 16 interrupt sources. Additional interrupt sourcesmay be placed at the same interrupt level bydaisy-chaining multipleCMFPs.The CMFPswill be prioritized bytheir position in the chain.

INTERRUPTPROCESSING Each CMFP provides individual interrupt capability

for itsvarious functions. When aninterrupt isreceivedononeofthe external interrupt channels or from oneof theeight internal sources,the CMFP willrequest interrupt service. The 16 interrupt channels areassigneda fixedpriorityso thatmultiplepending interrupts areservicedaccordingto theirrelativeimportance. Since the CMFP can internally generate 16vectornumbers, the unique vectornumber which corresponds to the highest priority channel that as apending interrupt ispresented totheprocessorduring an interrupt acknowledge cycle. This unique vectornumber allows theprocessor to immediately

beginexecution of theinterrupt handler fortheinterrupt source,decreasing interrupt latencytime.

INTERRUPTCHANNEL PRIORITIZATION The 16 interrupt channels are prioritized as shown

in figure5. General purpose interrupt 7(I7)is thehighest priority interrupt channel and I0 is the lowest priority channel.Pendinginterruptsarepresented to the CPU in order of priority unless theyhave been masked off. By selectively masking interrupts, the channelare in effectre-prioritized.

INTERRUPTVECTORNUMBER FORMAT During an interrupt acknowledge cycle,a unique 8-

bit vector number is presented to the systemwhich corresponds tothespecificinterrupt source which is requesting service. The format of the vector is shown in figure 6. The most significant four bits of the interruptvectornumberareuserprogrammable. These bits are set by writing the upper four bits of the vector register which is shown in figure 7. The low order bits are generated internally by the TS68HC901. Note that the binary channel number shown in figure 5 corresponds to the low order bits of thevector number associated witheach channel.

Figure 9 : Interrupt Channel Prioritization

Figure 5 : Interrupt Channel Prioritization

Priority Channel Descriptio n

HIGHEST

LOWEST

1111 1110 1101 1100 1011 1010 1001 1000 0111 0110 0101 0100 0011 0010 0001 0000

General Purpose Interrupt 7(I7) General Purpose Interrupt 6(I6) Timer A Receive Buffer Full Receive Error Transmit Buffer Empty Transmit Error Timer B General Purpose Interrupt 5(I5) General Purpose Interrupt 4(I4) Timer C Timer D General Purpose Interrupt 3(I3) General Purpose Interrupt 2(I2) General Purpose Interrupt 1(I1) General Purpose Interrupt 0(I0)

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V7 V6 V5 V4 IV3 IV2 IV1 IV0

V7-V4 The four mostsignificant bitsare copied from the register IV3-IV0 These bitsare supplied by the CMFP.They are thebinary channel number of the highest

priority channel that is requesting interrupt service.

Figure 6 :

Figure 7 :

(17h)

V7 V6 V5 V4 S 0* 0* 0*

Writin g 0 : CLEARED Writing 1 : SET CLEARED on RESET

VECTOR REGISTER

V7-V4 The upper fourbitsof the vectorregister are writtenby the user. These bits become themost

significant four bits of the interrupt vector number.

S In-Service Register Enable. When the Sbit is zero,the CMFP isin the automatic end-of-in-

terrupt mode and the In-Service register bits are forced low. When the S bit is a one, the CMFP isin the software end-of-interrupt mode and the In-Service register bits areenabled.

* Unused bits,read as zero.

Figure 8 : Daisy Chaining

TS68HC901 TS68HC901

TS68HC901

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TS68HC901

DAISY-CHAINING CMFPs As an interrupt controller, the TS68HC901 CMFP

willsupport eight external interrupt sources in addition to its eight internal interrupt sources. When a system requires more than eight external interrupt sources to be placed at the same interrupt level, sourcesmaybe added totheprioritized structureby daisy-chaining CMFPs. Interrupt sources areprioritized internally within each CMFP and the CMFPs areprioritized by their position inthe chain. Unique vector numbers are provided for each interrupt sources.

The IEI and IEO signals implement the daisy-chainedinterrupt structure.TheIEIofthehighest priority CMFPis tied low and the IEO output of this device is tied to the next highest priority CMFP’s IEI. The

IEI andIEO signalsaredaisy-chainedinthismanner for all CMFPs in the chain, with the lowest priority CMFP’s IEO left unconnected. A diagram of an interrupt daisy-chain is shownin figure8.

Daisy-chaining requires that all parts in the chain have a commonIACK. Whenthe common IACK is asserted duringan interrupt acknowledge cycle, all partswillprioritize interrupts inparallel.Whenthe IEI signalto aCMFP is asserted, the part may respond to the IACK cycle if it requires interrupt service. Otherwise,the partwill assert IEO tothe next lower priority device. Thus, priority is passed down the chainvia IEI andIEO until a part whichhas appending interrupt isreached. Thepart with the pending interrupt passes a vector number to the processor and doesnot propagate IEO.

Figure 9a :

Figure 9b :

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TS68HC901

INTERRUPTCONTROL REGISTERS CMPFinterruptprocessing ismanagedbytheinter-

rupt enable registers A andB, interrupt pending registersA andB, andinterrupt mask registers A and B.These registers allow theprogrammer to enable or disable individual interrupt channels, mask individual interrupt channels,and accesspending interruptstatusinformation. In-service registers Aand B allow interrupts tobe nestedas describedhereafter. The interrupt control registers are shown in figure10.

INTERRUPTENABLE REGISTERS Theinterrupt channels are individually enabled ordi-

sabledby writing a one or zero,respectively, tothe appropriate bit of interrupt enable register A(IERA) or interrupt enable register B (IERB).Theprocessor may readthese registers at anytime.

When a channel is enabled, interrupts received on the channel will be recognized by the CMFP and IRQwillbe asserted tothe processor,indicatingthat interrupt service isrequired. On the otherhand, adisabledchannel is completely inactive; interrupts receivedon the channel are ignored by theCMFP.

Writinga zero to a bitof interrupt enable register A orB willcausethecorresponding bitofinterrupt pendingregister A orB tobe cleared. This willterminate allinterrupt service requests forthe channel and also negate IRQ,unless interrupts are pending from other sources. Disabling a channel, however,does not affect the corresponding bit in interrupt in-serviceregistersA or B. So, if theCMFPis in thesoftware end-of-interrupt mode and an interrupt is in service whena channel will remainset until cleared bysoftware.

INTERRUPTPENDINGREGISTERS When aninterrupt is received onan enabled chan-

nel, the corresponding interrupt pending bitis set in interrupt pending register A orB (IPRAor IPRB). In a vectoredinterruptscheme, thisbit willbe cleared when the processor acknowledges the interrupting channeland the CMFPresponds witha vectornumber. In a polled interrupt system, the interrupt pending registers must be read to determine the interruptingchannel andthentheinterrupting pending bit is cleared by the interrupt handling routine without performing aninterrupt acknowledge sequence.

A singlebit of theinterrupt pending registers iscleared insoftwareby writing onesto all bitpositionsexcept thebit to be cleared. Note that writing ones to IPRA and IPRB has no effect on the contents of the register. A single bit of the interrupt pending registersisalsoclearedwhenthecorresponding channel is disabled bywriting azero tothe appropriate bitof IERA orIERB.

INTERRUPTMASK REGISTERS Interrupts are masked for a channel by clearing the

appropriate bitin interrupt mask register Aor B(IMRA or IMRB). Even though an enabled channel is masked, the channel will recognize subsequent interruptsand set its interrupt pending bit. However, the channel is prevented from requesting interrupt service(IRQ tothe processor) as long as the mask bit forthat channel is cleared.

If achannelisrequestinginterruptserviceatthetime that its corresponding bit in IMRA or IMRBis cleared, the request will ceaseandIRQ will benegated, unless anotherchannel is requesting interrupt service.Later,whenthemaskbit isset,any pendinginterrupt on thechannel will be processed according to the channel’s assigned priority. IMRAand IMRB may be read at any time.

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Figure 10 :

IERA (07h)

IERB (09h)

IPRA (0Bh)

IPRB (0Dh)

ISRA (0Fh)

GPIP7 GPIP6 TIMER A

GPIP5 GPIP4 TIMER C TIMER D GPIP3 GPIP2 GPIP1 GPIP0

GPIP7 GPIP6 TIMER A

GPIP5 GPIP4 TIMER C TIMER D GPIP3 GPIP2 GPIP1 GPIP0

Writing0:CLEAR Wri ting 1 : UNCHANG ED

GPIP7 GPIP6 TIMER A

INTERRUPT ENABLEREGISTERS

RCV

Buffer full

RCV

Error

XMIT

Buffer Empty

INTERRUPT PENDING REGISTERS

RCV

Buffer full

RCV

Error

XMIT

Buffer Empty

INTERRUPT IN-SERVICEREGISTERS

RCV

Buffer full

RCV

Error

XMIT

Buffer Empty

XMIT Error

TIMER B

ISRB (11h)

IMRA

(13h)

IMRB

(15h)

GPIP5 GPIP4 TIMER C TIMER D GPIP3 GPIP2 GPIP1 GPIP0

GPIP7 GPIP6 TIMER A

GPIP5 GPIP4 TIMER C TIMER D GPIP3 GPIP2 GPIP1 GPIP0

Writing 0 : MASKED Writing 1 : UN MASKED

INTERRUPT MASK REGISTERS

RCV

Buffer full

RCV

Error

Buffer Empty

XMIT

XMIT Error

TIMER B

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