U-Timer Operation; Figure 9.3-1 Example Of Using U-Timer Channels 0 And 1 In Cascade Mode - Fujitsu MB91F109 FR30 Hardware Manual

9.3

U-TIMER Operation

This section explains how to calculate the U-TIMER baud rate and also explains the
cascade mode.
Calculating the Baud Rate
The UART uses the underflow flip-flop (f.f. in the figure) of the corresponding U-TIMER (U-
TIMERx --> UARTx, x = 0, 1, 2) as the baud rate clock source.
Asynchronous (start-stop) mode
The UART uses the U-TIMER output by dividing it by 16.
bps =
(2n+2)
bps =
(2n+3)
CLK synchronous mode
bps =
(2n+2)
bps =
(2n+3)
Cascade Mode
U-TIMER channels 0 and 1 can be used in cascade mode. Figure 9.3-1 shows an example of
cascade mode in which UTIMR channel 0 is set to 0100 and UTIMR channel 1 is set to 0002.

Figure 9.3-1 Example of Using U-TIMER Channels 0 and 1 in Cascade Mode

UTIM ch.1 01 00
f.f. ch.1
UTIM ch.0 0002
f.f. ch.0
16
16
UCC1=0
UCC1=1
02 01 00 02 01
n: UTIMR (Reload value)
UCC1=0
: Peripheral machine clock frequency
(variable with the gear)
UCC1=1
n: UTIMR (Reload value)
00 02 01 00 02
0001
9.3 U-TIMER Operation
: Peripheral machine clock frequency
(variable with the gear)
01 00 02 01 00
0000
02 01 00
0100
243