gonzalez@bbn.com (Jim Gonzalez) (11/14/90)
I am in the process of getting a Northstar HSIO (serial interface) board working on a Cromemco System Three (S-100 bus with a Z-80). The CPU board apparently produces a 4MHz clock, while the serial board expects to be clocked at 2MHz. I could adjust the baud rate specification by a factor of 2 (yielding 1200 baud when I tell it to run at 600, for example), except the 8251 is only rated to run up to 2.4MHz. The 8251A is rated for a maximum of 3MHz, so a chip upgrade won't help either. Des anyone know if there is a faster version of the 8251 available? My information comes from the 1987 ediiton of an Advanced Micro Devices data book. The part must be a drop-in; if I have to do any cutting I may as well just build a new board. -Jim.