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Semiconductor Group
47
On-Chip Peripheral Components
7.2
Serial Interfaces
The serial port of the SAB 80(C)515S enables communication between microcontrollers or between
the microcontroller and peripheral devices.
The serial port is full-duplex, meaning it can transmit and receive simultaneously. It is also receive
buffered, meaning it can commence reception of a second byte before a previously received byte
has been read from the receive register (however, if the first byte still has not been read by the time
reception of the second byte is complete, the last received byte will be lost). The serial channel is
completely compatible with the serial channel of the SAB 80(C)51.
7.2.1
Operating Modes of Serial Interface
The serial interface can operate in four modes (one synchronous mode, three asynchronous
modes). The baud rate clock for this interface is derived from the oscillator frequency (mode 0, 2)
or generated either by timer 1 or by a dedicated baud rate generator (mode 1, 3). A more detailed
description of how to set the baud rate will follow in section 7.2.3.
Mode 0: shift register (synchronous) mode:
Serial data enters and exits through RxD. TxD outputs the shift clock. 8 data bits are transmitted/
received (LSB first). The baud rate is fixed at 1/12 of the oscillator frequency.
Mode 1: 8-bit UART, variable baud rate:
10 bits are transmitted (through TxD) or received (through RxD): a start bit (0), 8 data bits (LSB first),
and a stop bit (1). On reception, the stop bit goes into RB8 in special function register SCON. The
baud rate is variable.
Mode 2: 9-bit UART, fixed baud rate:
11 bits are transmitted (through TxD) or received (through RxD): a start bit (0), 8 data bits (LSB first),
a programmable 9th bit, and a stop bit (1). On transmission, the 9th data bit (TB8 in SCON) can be
assigned to the value of 0 or 1. For example, the parity bit (P in the PSW) could be moved into TB8
or a second stop bit by setting TB8 to 1. On reception the 9th data bit goes into RB8 in special
function register SCON, while the stop bit is ignored. The baud rate is programmable to either 1/32
or 1/64 of the oscillator frequency.
Mode 3: 9-bit UART, variable baud rate:
11 bits are transmitted (through TxD) or received (through RxD): a start bit (0), 8 data bits (LSB first),
a programmable 9th bit, and a stop bit (1). On transmission, the 9th data bit (TB8 in SCON) can be
assigned to the value of 0 or 1. For example, the parity bit (P in the PSW) could be moved into TB8
or a second stop bit by setting TB8 to 1. On reception, the 9th data bit goes into RB8 in special
function register SCON, while the stop bit is ignored. In fact, mode 3 is the same as mode 2 in all
respects except the baud rate. The baud rate in mode 3 is variable.
*
Содержание SAB 80515 Series
Страница 9: ...Semiconductor Group 9 Introduction Figure 1 2 Block Diagram ...
Страница 12: ...Semiconductor Group 12 Fundamental Structure Figure 2 1 Detailed Block Diagram ...
Страница 18: ...Semiconductor Group 18 Central Processing Unit Figure 3 1 Fetch Execute Sequence ...
Страница 22: ...Semiconductor Group 22 Memory Organization Figure 4 3 Mapping of the Lower Portion of the Internal Data Memory ...
Страница 30: ...Semiconductor Group 30 External Bus Interface Figure 5 1 a and b External Program Memory Execution ...
Страница 38: ...Semiconductor Group 38 On Chip Peripheral Components Figure 7 3 Output Driver Circuits of Ports 1 through 5 ...
Страница 59: ...Semiconductor Group 59 On Chip Peripheral Components Figure 7 16 a Functional Diagram Serial Interface Mode 0 ...
Страница 60: ...Semiconductor Group 60 On Chip Peripheral Components Figure 7 16 b Timing Diagram Serial Interface Mode 0 ...
Страница 61: ...Semiconductor Group 61 On Chip Peripheral Components Figure 7 17 a Functional Diagram Serial Interface Mode 1 ...
Страница 62: ...Semiconductor Group 62 On Chip Peripheral Components Figure 7 17 b Timing Diagram Serial Interface Mode 1 ...
Страница 73: ...Semiconductor Group 73 On Chip Peripheral Components Figure 7 25 A D Converter Block Diagram ...
Страница 83: ...Semiconductor Group 83 On Chip Peripheral Components Figure 7 33 a Timer 2 Block Diagram ...
Страница 111: ...Semiconductor Group 111 On Chip Peripheral Components Figure 7 54 Timing Diagram System Clock Output ...
Страница 113: ...Semiconductor Group 113 Interrupt System Figure 8 1 a Interrupt Structure of the SAB 80 C 515 80 C 535 ...
Страница 114: ...Semiconductor Group 114 Interrupt System Figure 8 1 b Interrupt Structure of the SAB 80 C 515 80 C 535 cont d ...
Страница 204: ...Semiconductor Group 204 Instruction Set XCH A Ri Operation XCH A Ri Bytes 1 Cycles 1 Encoding 1 1 0 0 0 1 1 i ...
Страница 215: ...Device Specifications Semiconductor Group 215 ...
Страница 217: ...Device Specifications Semiconductor Group 217 Pin Configuration P LCC 68 ...
Страница 219: ...Device Specifications Semiconductor Group 219 Logic Symbol ...
Страница 226: ...Device Specifications Semiconductor Group 226 Figure 1 Block Diagram ...
Страница 229: ...Device Specifications Semiconductor Group 229 Figure 2 Memory Address Spaces ...
Страница 239: ...Device Specifications Semiconductor Group 239 Figure 4 Block Diagram of the A D Converter ...
Страница 241: ...Device Specifications Semiconductor Group 241 Figure 5 Interrupt Request Sources ...
Страница 242: ...Device Specifications Semiconductor Group 242 Figure 6 Interrupt Priority Level Structure ...
Страница 268: ...Device Specifications Semiconductor Group 268 AC Testing Input Output Waveforms AC Testing Float Waveforms ...