Rainbow Electronics AT75C220 - Manual (Page 85)

AT75C220
85
USART Mode Register
Name: US_MR
Access Type:Read/write
Reset Value:0x0
• USCLKS: Clock Selection (Baud Rate Generator Input Clock)
• CHRL: Character Length
Start, stop and parity bits are added to the character length.
• SYNC: Synchronous Mode Select
0 = USART operates in asynchronous mode.
1 = USART operates in synchronous mode.
• PAR: Parity Type
31 30 29 28 27 26 25 24
– – – – – – – –
23 22 21 20 19 18 17 16
– – – – – CLKO MODE9 –
15 14 13 12 11 10 9 8
CHMODE NBSTOP PAR SYNC
7 6 5 4 3 2 1 0
CHRL USCLKS – – – –
USCLKS Selected Clock
0 0 ACLK
0 1 ACLK/8
1 X External (SCK)
CHRL Character Length
0 0 Five bits
0 1 Six bits
1 0 Seven bits
1 1 Eight bits
PAR Parity Type
0 0 0 Even parity
0 0 1 Odd parity
0 1 0 Parity forced to 0 (space)
0 1 1 Parity forced to 1 (mark)
1 0 x No parity
1 1 x Multi-drop mode