OSBYTE &08
From BeebWiki
OSBYTE &08 (8) - Select the transmit rate to be used on the RS423 interface.
On entry, A=&08, X=transmission rate
On exit, A=&07, X=Y=previous contents of Serial ULA control register (B+ User Guide)
The value of X is made up as follows:
| Value | Meaning if set |
|---|---|
| 1 | 75 baud transmit |
| 2 | 150 baud transmit |
| 3 | 300 baud transmit |
| 4 | 1200 baud transmit |
| 5 | 2400 baud transmit |
| 6 | 4800 baud transmit |
| 7 | 9600 baud transmit |
| 8 | 19200 baud transmit. This rate is not guaranteed. |
A baud rate can be converted to a *FX7/*FX8 parameter with the following code:
A%=baud%:IFA%>63:A%=LN(A%DIV75)/LN2:IFA%<4:A%=A%+1
A *FX7/8 parameter can be converted into a baud rate with the following code:
A%=rate%:IFA%<64:A%=A%+(A%<4):A%=75*2^A%
See also
- OSBYTE &07 - Set serial receive rate
- OSBYTE &9C - Set serial control parameters
