tmp1941af TOSHIBA Semiconductor CORPORATION, tmp1941af Datasheet - Page 205

• Manufacturer Part Number: tmp1941af
• Description: 32-bit Tx System Risc
• Manufacturer: TOSHIBA Semiconductor CORPORATION

(3) Calculation Examples
(4) Using an External Clock as a Serial Clock
generator. When an external clock is used, the baud rate is determined as shown below.
•
•
clock inputs and clock divisor values.
•
The SIO0 and SIO1 can use an external clock as a serial clock, bypassing the baud rate
Table 13.3 and Table 13.4 show the UART baud rates obtained with various combinations of
Clocking conditions
The baud rate is determined as follows:
= 24.576 × 10
Clocking conditions
The baud rate is determined as follows:
Integral Clock Division (Divide-by-N)
fperiph = 24.576-MHz fc
φT0 = fperiph/4
Baud rate generator input clock: φT2
Clock divisor N (BR0CR.BR0S[3:0]) = 10
BR0CR.BR0ADDE = 0
N + (16 – K) / 16 Clock Division (UART mode only)
fperiph = 19.2-MHz fc
φT0 = fperiph/4
Baud rate generator input clock: φT2
N (BR0CR.BR0S[3:0]) = 7
K (BR0ADD.BR0K[3:0]) = 3
BR0CR.BR0ADDE = 1
UART Mode
40 MHz, the maximum baud rate is 625 kbps (40 ÷ 4 ÷ 16).
Note:
Baud Rate = external clock input ÷ 16
The external clock period must be greater than or equal to 4/fsys. Therefore, when fsys =
System clock:
High-speed clock gear:¤1 (fc)
Prescaler clock:
Baud Rate =
System clock:
High-speed clock gear:¤1 (fc)
Prescaler clock:
Baud Rate =
= 19.2 × 10
Clearing the BR0CR.BR0ADDE bit to 0 disables the N + (16 – K) / 16 clock division
function. At this time, the BR0ADD.BR0K[3:0] field is ignored.
6
6
÷ 16 ÷ 10 ÷ 16 = 9600 (bps)
÷ 16 ÷ (7 +
fc/16
7
10
+
fc
(16
/
16
16
÷ 16
TMP1941AF-165
-
3)
High-speed (fc)
fperiph/4 (fperiph = fsys)
High-speed (fc)
fperiph/4 (fperiph = fsys)
÷ 16
13
16
) ÷ 16 = 9600 (bps)
TMP1941AF
2003-03-27