Appendix A. Supported Rabbit 2000 Baud Rates

This table contains divisors to put into TATxR registers. All frequencies that allow 57600 baud up to 30MHz are shown (as well as a few higher frequencies):

Crystal Freq. (MHz)	Example Boards	2400 baud	9600 baud	19200 baud	57600 baud	115200 baud
1.8432		23	5	2	0	-
3.6864	BL1800 divided by 8	47	11	5	1	0
5.5296		71	17	8	2	-
7.3728	BL1810, not doubled	95	23	11	3	1
9.2160	RCM2020, not doubled	119	29	14	4	-
11.0592	RCM2100, not doubled	143	35	17	5	2
12.9024	RCM2000. not doubled	167	41	20	6	-
14.7456	BL1820, doubled	191	47	23	7	3
16.5888		215	53	26	8	-
18.4320	TCP/IP Dev. Kit	239	59	29	9	4
20.2752		*	65	32	10	-
22.1184	RCM2100, doubled	*	71	35	11	5
23.9616		*	77	38	12	-
25.8048	RCM2010, doubled	*	83	41	13	6
27.6480		*	89	44	14	-
29.4912	BL1800 (can't double)	*	95	47	15	7
36.8640		*	119	59	19	9
44.2368		*	143	71	23	11

This information is calculated with the following equation:

divisor = (crystal frequency in Hz) / (32 * baud rate) - 1

If the divisor is not an integer value, that baud rate is not available for that frequency (identified by a "-" in the table).

If the divisor is above 255, that baud rate is not available without further BIOS modification (identified by a "*" in the table). To allow that baud rate, you need to clock the serial port desired via timer A (by default they run off the CPU clock / 2), then scale down timer A to make the serial port divisor fall below 256.