Asynchronous Serial Port | AMD Am188TMER, Am186TMER guide

CHAPTER

11 ASYNCHRONOUS SERIAL PORT

11.1OVERVIEW

The Am186ER and Am188ER microcontrollers provide an asynchronous serial port. The asynchronous serial port is a two-pin interface that permits full-duplex bidirectional data transfer. The asynchronous serial port supports the following features:

νFull-duplex operation

ν7-bit or 8-bit data transfers

νOdd parity, even parity, or no parity

ν1 or 2 stop bits

If additional RS-232 signals are required, they can be created with available PIO pins (see section 13.1 on page 13-1). The asynchronous serial port transmit and receive sections are double-buffered. Break character recognition, framing, parity, and overrun error detection are provided. Exception interrupt generation is programmed by the user.

The transmit/receive clock is based on the internal processor clock internally divided down to the serial port operating frequency. If power-save mode is in effect, the divide factor must be reprogrammed. The serial port permits 7-bit and 8-bit data transfers. DMA transfers through the serial port are not supported.

The serial port generates one interrupt for all serial port events (transmit complete, data received, or error). The Serial Port Status register contains the reason for the serial port interrupt. The interrupt type assigned to the serial port is 14h.

The serial port can be used in power-save mode, but the transfer rate must be adjusted to correctly reflect the new internal operating frequency and the serial port must not receive any information until the frequency is changed.

11.2PROGRAMMABLE REGISTERS

The asynchronous serial port is programmed through the use of five, 16-bit peripheral registers. See Table 11-1.

Table 11-1 Asynchronous Serial Port Register Summary

Offsetfrom	Register
PCB	Mnemonic	Register Name

80h	SPCT	Serial Port Control

82h	SPSTS	Serial Port Status

84h	SPTD	Serial Port Transmit Data

86h	SPRD	Serial Port Receive Data

88h	SPBAUD	Serial Port Baud Rate Divisor

Asynchronous Serial Port

11-1

Image 149

AMD Am188TMER, Am186TMER user manual Asynchronous Serial Port Register Summary Offsetfrom, Asynchronous Serial Port 11-1

Contents

Am186äER and Am188äER Microcontrollers User’s Manual Advanced Micro Devices, Inc. All rights reserved If YOU have QUESTIONS, WE’RE Here to Help YOU Customer ServiceHotline and World Wide Web Support Documentation and LiteraturePage Table of Contents Chip Select Unit Timer Control Unit Chapter DMA Controller Viii Table of Contents PCS MCS List of Figures Figure A-1 Processor Release Level PRL Register High-Order Byte Values List of Tables Xii Table of Contents Design Philosophy Introduction and OverviewPurpose of this Manual Intended Audience E86 Microcontroller Family AMD Documentation Features and Performance Features and PerformanceKEY Features and Benefits Distinctive Characteristics Features and Performance Am186ER Microcontroller Block Diagram Am188ER Microcontroller Block Diagram Clock Generation Application Considerations Serial Communications Port Memory Interface THIRD-PARTY Development Support Products Programming ProgrammingRegister SET Bits 15-12 -Reserved Processor Status Flags Register Bit 5 Reserved Memory Organization and Address GenerationBit 3 Reserved Bit 1 Reserved Instruction SET I/O Space Mnemonic Instruction Name Instruction Set JB/JNAE OUT Data Types SegmentsSegment Register Selection Rules Segment Register Implicit Segment Selection Rule Supported Data Types Addressing Modes Memory Addressing Mode ExamplesRegister and Immediate Operands Memory Operands PIN Descriptions System OverviewPin Terminology A19-A0 Address Bus output, three-state, synchronous Aden Address Latch Enable output, synchronous Address Enable, Am186ER Microcontroller Only Bus High Enable, Am186ER Microcontroller OnlyAsynchronous Ready input, asynchronous, level-sensitive Three-state, output, synchronous Clock Output a output, synchronous Data Enable output, three-state, synchronousClock Output B output, synchronous DMA Requests input, synchronous, level-sensitive Maskable Interrupt Request 0 input, asynchronous Bus Hold Request input, synchronous, level-sensitiveMaskable Interrupt Request 1 input, asynchronous Slave Select input, asynchronous Interrupt Acknowledge 0 output, synchronous Maskable Interrupt Request 2 input, asynchronousMaskable Interrupt Request 3 input, asynchronous Interrupt Acknowledge 1 output, synchronous Midrange Memory Chip Select Once Mode Request 0 inputOutput, synchronous, internal pullup Automatic Refresh output, synchronous Peripheral Chip Select 5 output, synchronous Peripheral Chip Selects output, synchronousLatched Address Bit 1 output, synchronous Peripheral Chip Select 6 output, synchronous System Overview PIO Pin Assignments-Numeric Listing PIO No Associated Pin Power-On Reset Status PIO Pin Assignments-Alphabetic Listing Associated Pin PIO No Power-On Reset Status Address Enable input, internal pullup Reset input, asynchronous, level-sensitiveRead Strobe output, synchronous, three-state Refresh 2 three-state, output, synchronous Show Read Enable input, internal pullup Internal Memory Disable input, internal pullupBus Cycle Status output, three-state, synchronous Bus Cycle Status Bit 6 output, synchronous Timer Input 0 input, synchronous, edge-sensitive Serial Data Enables output, synchronousSerial Clock output, synchronous, three-state Serial Data input/output, synchronous Timer Output 0 output, synchronous Timer Input 1 input, synchronous, edge-sensitiveTimer Output 1 output, synchronous Once Mode Request 1 input, internal pullup Write High Byte, Am186ER Microcontroller Only Power Supply inputOutput, three-state, synchronous Write Low Byte, Am186ER Microcontroller Only Pins That Are Used by Emulators BUS Operation Clkouta A19-A0 Address AD7-AD0 BUS Interface Unit Byte Write EnablesNonmultiplexed Address Bus Pseudo Static RAM Psram Support System Overview Phase-Locked Loop PLL Clock and Power Management UnitMaximum and Minimum Clock Frequencies Mode X1/X2 Min External Source Clock Crystal-Driven Clock Source System Clocks Power-Save Operation System Overview Peripheral Control Block Peripheral Control BlockOverview Peripheral Control Block Register Map Timer 1 Count Register Bit 13 Reserved Bit 15 Reserved Reset Configuration Register RESCON, offset F6h Reset Configuration Register RESCON, Offset F6h Bits 7-0 Reserved -Value is undefined Processor Release Level Register PRL, Offset F4h Bits 7-3 Reserved -Read back as Power-Save Control Register PDCON, Offset F0h Divider Factor Initialization and Processor Reset Registers not listed in this table are undefined at reset Peripheral Control Block Chip Select Unit Chip Select Unit Chip Select Overlap Chip Select TimingReady and WAIT-STATE Programming Chip Select Registers Bit 15 Reserved-Set to Upper Memory Chip Select Register UMCS, Offset A0hUmcs Block Size Programming Values Memory Block Starting Bits 6 Reserved- Set to Bits 5-3 Reserved- Set to Bits 11-8 Reserved Memory Block Ending Low Memory Chip Select Register LMCS, Offset A2hLmcs Block Size Programming Values Bits 11-8 Reserved- Set to Midrange Memory Chip Select Register MMCS, offset A6h Midrange Memory Chip Select Register MMCS, Offset A6h Bits 8-3 Reserved -Set to Bit 15 Reserved- Set to PCS and MCS Auxiliary Register MPCS, Offset A8hMCS Block Size Programming Total Block Individual Bits 5-3 Reserved -Set to Peripheral Chip Select Register PACS, offset A4h Peripheral Chip Select Register PACS, Offset A4h PCS Address Ranges Line Bits 6-4 Reserved -Set toLow High PCS3-PCS0 Wait-State Encoding Wait States Chip Select Unit Internal Memory Internal MemoryInteraction with External RAM Emulator and Debug Modes Internal Memory DisableShow Read Enable Bits 8-0 Reserved -Set to Internal Memory Chip Select Register IMCS, Offset ACh Internal Memory Memory Partition Register MDRAM, Offset E0h Refresh Control UnitBits 8-0 Reserved -Read back as Refresh Control Unit Bits 14-9 Reserved -Read back as Enable RCU Register EDRAM, Offset E4hClock Prescaler Register CDRAM, Offset E2h Definitions of Interrupt Terms Interrupt Control UnitInterrupt Type Interrupt Vector Table Maskable and Nonmaskable Interrupts Interrupt Enable Flag ifInterrupt Mask Bit Interrupt Priority Overall Software ExceptionsAm186ER and Am188ER Microcontroller Interrupt Types Interrupt Conditions and Sequence Maskable Hardware Interrupt Priority Interrupt PriorityNonmaskable Interrupts and Software Interrupt Priority Software Exceptions, Traps, and NMI Divide Error Exception Interrupt Type 00hTrace Interrupt Interrupt Type 01h Nonmaskable Interrupt-NMI Interrupt Type 02h Into Detected Overflow Exception Interrupt Type 04h Breakpoint Interrupt Interrupt Type 03hArray Bounds Exception Interrupt Type 05h Unused Opcode Exception Interrupt Type 06h External Interrupt Acknowledge Bus Cycles Interrupt Acknowledge Interrupt Controller Reset Conditions Fully Nested Mode Master Mode Operation Cascade Mode Interrupt Controller Connections Cascade Mode End-of-Interrupt Write to the EOI Register Special Fully Nested ModeOperation in a Polled Environment Master Mode Interrupt Controller Registers Value of I0CON and I1CON at reset is 000Fh Priority Level Bits 15-5 Reserved -Set to INT4 Control Register I4CON, offset 40h 3 INT4 Control Register I4CON, Offset 40h Master Mode Bits 15-4 Reserved -Set to Value of Wdcon at reset is 000Fh Serial Port Interrupt Control Register SPICON, offset 44h Bits 15-5 Reserved -Set to Bit 4 Reserved-Set to 10 Interrupt Status Register INTSTS, offset 30h Interrupt Status Register INTSTS, Offset 30h Master Mode Bits 15-11 Reserved Interrupt Request Register REQST, Offset 2Eh Master Mode 12 In-Service Register INSERV, offset 2Ch In-Service Register INSERV, Offset 2Ch Master Mode Priority Field Mask Master Mode PR2-PR0 Priority Mask Register PRIMSK, Offset 2Ah Master Mode 14 Interrupt Mask Register IMASK, offset 28h Interrupt Mask Register IMASK, Offset 28h Master Mode Bits 14-5 Reserved -Set to Poll Status Register POLLST, Offset 26h Master Mode 16 Poll Register POLL, offset 24h Poll Register POLL, Offset 24h Master Mode Bits 14-5 Reserved End-of-Interrupt Register EOI, Offset 22h Master Mode Slave Mode Interrupt Controller Registers Slave Mode OperationSlave Mode Interrupt Nesting These registers are set to 000Fh on reset 20 Interrupt Status Register INTSTS, offset 30h Interrupt Status Register INTSTS, Offset 30h Slave Mode 21 Interrupt Request Register REQST, offset 2Eh Interrupt Request Register REQST, Offset 2Eh Slave Mode 22 In-Service Register INSERV, offset 2Ch In-Service Register INSERV, Offset 2Ch Slave Mode Priority Field Mask Slave Mode PR2-PR0 Priority Mask Register PRIMSK, Offset 2Ah Slave Mode 24 Interrupt Mask Register IMASK, offset 28h Interrupt Mask Register IMASK, Offset 28h Slave Mode 25 Specific End-of-Interrupt Register EOI, offset 22h Bits 15-3 Reserved -Write as Bits 2-0 Reserved -Read as Interrupt Vector Register INTVEC, Offset 20h Slave ModeBits 15-8 Reserved -Read as Interrupt Control Unit Timer Control Unit Register Summary Offsetfrom Timer Control UnitTimer Control Unit Programmable Registers Timer Operating Frequency Bits 11-6 Reserved -Set to Timer Control Unit Bits 4-1 Reserved -Set to Timer 2 Mode and Control Register T2CON, Offset 66hBits 12-6 Reserved -Set to TC15-TC0 Value of these registers at reset is undefined Timer Control Unit DMA Operation DMA ControllerDMA Controller Register Summary Offsetfrom DMA Controller 10-1 10-2 DMA Controller Programmable DMA Registers DMA Controller 10-3 DMA Control Registers D0CON, Offset CAh, D1CON, Offset DAh 10-4 DMA Controller Synchronization TypeSync Type DMA Controller 10-5 DMA Transfer Count Registers D0TC, D1TC, offsets C8h and D8h 10-6 DMA Controller DMA Controller 10-7 10-8 DMA Controller DMA Controller 10-9 10-10 DMA Controller DMA Requests Source Synchronization Timing Synchronization TimingDestination Synchronization Timing DMA Controller 10-11 DMA Priority DMA AcknowledgeDMA Programming 10-12 DMA Controller DMA Controller 10-13 DMA Channels on Reset 10-14 DMA Controller Asynchronous Serial Port 11-1 Asynchronous Serial PortAsynchronous Serial Port Register Summary Offsetfrom 11-2 Asynchronous Serial Port Serial Port Control Register SPCT, Offset 80h Asynchronous Serial Port 11-3 Parity Mode Bit Settings 11-4 Asynchronous Serial Port Serial Port Status Register SPSTS, Offset 82hBits 15-7 Reserved -Set to Asynchronous Serial Port 11-5 Serial Port Transmit Data Register SPTD, Offset 84hBits 15-8 Reserved 11-6 Asynchronous Serial Port Serial Port Receive Data Register SPRD, Offset 86h Asynchronous Serial Port 11-7 Serial Port Baud Rate Divisor Register SPBAUD, Offset 88h 11-8 Asynchronous Serial Port Synchronous Serial Interface 12-1 Synchronous Serial InterfaceSynchronous Serial Interface Register Summary Offset from 12-2 Synchronous Serial Interface Four-Pin Interface Synchronous Serial Interface 12-3 Synchronous Serial Status Register SSS, Offset 10h Bits 3-2 Reserved -Set to Synchronous Serial Control Register SSC, Offset 12hBits 15-6 Reserved -Set to Synchronous Serial Interface 12-5 Bits 15-8 Reserved -Set to 12-6 Synchronous Serial Interface Synchronous Serial Receive Register SSR, Offset 18h Synchronous Serial Interface 12-7 SSI Programming Synchronous Serial Interface Multiple Read Synchronous Serial Interface Multiple Write Programmable I/O Pins 13-1 Programmable I/O Pins 13-2 Registers PIOMODE1, 76h PDIR0, 78h PDATA0, 7Ah PIO Mode 1 Register PIOMODE1, Offset 76h PIO Mode RegistersPIO Mode 0 Register PIOMODE0, Offset 70h PIO Mode and PIO Direction Settings Pin Function PIO Direction 1 Register PDIR1, Offset 78h PIO Direction RegistersPIO Direction 0 Register PDIR0, Offset 72h 13-4 PIO Data Registers Programmable I/O Pins 13-5PIO Data Register 1 PDATA1, Offset 7Ah PIO Data Register 0 PDATA0, Offset 74h 13-6 Register Summary Register Summary Rescon T1CMPB Figure A-1 Internal Register Summary Memory Partition Register Mdram DMA 0 Control Register D0CON Internal Memory Chip Select Register Imcs Serial Port Baud Rate Divisor Register Spbaud PMODE15-PMODE0 Timer 2 Maxcount Compare a Register T2CMPA Timer 0 Maxcount Compare B Register T0CMPB Sfnm Interrupt Request Register Reqst Master Mode Interrupt Request Register Reqst Slave Mode Interrupt Mask Register Imask Interrupt Vector Register Intvec Slave Mode Index Index Index Index Index Index Index Index Index Index Index