[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system
hmurray at megapathdsl.net
Tue Nov 4 14:31:52 EST 2014
brooke at pacific.net said:
> UARTs are not mandatory, a simple transistor level shifting circuit is all
> that's needed for TTL/RS-232 levels.
I think you are confusing UARTs with level shifters.
In the old days, transistors were expensive enough that a 68000 class CPU was
all that could fit on a chip. All memory and peripherals were off chip.
While not quite mandatory, most of the time it made sense to use a UART chip.
If you had a FPGA, you could put a simple UART in there. (But back then,
FPGAs weren't very big either.) If the CPU was idle, you could bit-bang
These are my opinions. I hate spam.
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