Micronas SDA 6000, User Manual

Page: 218 / 412

SDA 6000
PRELIMINARY DATA SHEET
Version 2.1
Peripherals
7 - 60 Micronas
Figure 7-31 ASC0 Synchronous Mode Waveforms
7.3.3 Baud Rate Generation
The serial channel ASC0 has its own dedicated 13-bit baud rate generator with 13-bit
reload capability, allowing baud rate generation to be independent of the GPT timers.
The baud rate generator is clocked with the CPU clock. The baud rate timer is counting
downwards and can be started or stopped through the baud rate generator run bit S0R
in register S0CON. Each underflow of the timer provides one clock pulse to the serial
channel. The timer is reloaded with the value stored in its 13-bit reload register each time
it underflows. The resulting clock
f
BRT
is again divided according to the operating mode
and controlled by the baud rate selection bit S0BRS. If S0BRS = ‘1’, the clock signal is
additionally divided to 2/3rd of its frequency (see formulas and table). So the baud rate
of ASC0 is determined by the CPU clock, the reload value, the value of S0BRS and the
operating mode (asynchronous or synchronous).
UET11150
Receive Data
D0 D1 D2 D3 D4 D5 D6 D7 D0 D1 D2 D3
1. Byte 2. Byte
Transmit Data
D1 D0 D2 D0 D6
1. Byte
D3 D4 D5 D7 D1
2. Byte
D2 D3
Shift Clock
Continuous Transmit Timing
Data Bit n+1 Data Bit n+2 Data Bit n
Shift Clock
Transmit Data
Valid Data n
Receive Data
Valid Data n+1 Valid Data n+2
Shift Latch Shift Latch Shift
Receive/Transmit Timing