Rainbow Electronics AT75C220 - Manual (Page 92)

AT75C220
92
USART Baud Rate Generator Register
Name: US_BRGR
Access Type:Read/write
Reset Value: 0x0
• CD: Clock Divisor
This register has no effect if synchronous mode is selected with an external clock.
Note: In synchronous mode, the value programmed must be even to ensure a 50:50 mark-to-space ratio.
Note: Clock divisor bypass (CD = 1) must not be used when internal clock ACLK is selected (USCLKS = 0).
31 30 29 28 27 26 25 24
– – – – – – – –
23 22 21 20 19 18 17 16
– – – – – – – –
15 14 13 12 11 10 9 8
CD
7 6 5 4 3 2 1 0
CD
CD Effect
0 Disables clock
1 Clock divisor bypass
2 to 65535 Baud rate (asynchronous mode) = Selected clock/(16 x CD)
Baud rate (synchronous mode) = Selected clock/CD