Rainbow Electronics AT76C551 - Manual (Page 67)

67
AT76C551
1612D–08/01
US_RTO: Receiver Time-out Register
addr: 700024 hex R/W 8 bits
• Bits 7..0 – US_RTO[7:0]
This register contains the maximum period, for which the UART can wait before a character
arrives, during the time-out function. This function is disabled when this register is zero. The
value of register US_RTO represents bit periods
Note: Default Value: 00 hex
US_TTG: Transmitter Time Guard Register
addr: 700028 hex R/W 8 bits
• Bits 7..0 – US_TTG[7:0]
The value of this register indicates the delay (in bit periods) that an active transmitter has to
interpose between two consecutive character transmissions.
Note: Default Value: 00 hex
US_MCI Modem Control Inputs
addr: 70002C hex R 8 bits
• Bit 7 – DSR: Data Set Ready
Active high. This bit is the compliment of the DSR input pin.
• Bit 6 – RI: Ring Indicator
Active high. This bit is the compliment of the RI input pin.
Table 12. Baud Rate Generation Example (Internal UART Clock = 14,76923 MHz)
Baud Rate US_BM (hex) US_BL (hex) Error %
100 24 00 0.16
200 12 00 0.16
400 09 00 0.16
600 06 00 0.16
1200 03 00 0.16
2400 01 80 0.16
4800 00 C0 0.16
9600 00 60 0.16
19200 00 30 0.16
28800 00 20 0.16
38400 00 18 0.16
57.6K 00 10 0.16
115.2K 00 08 0.16
230.4K 00 04 0.16
307.2K 00 03 0.16
460.8K 00 02 0.16
921.6K 00 01 0.16