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5.12
DS-1302 RAM Parameters
This command should be run the first time you boot the P112 and whenever
the DS-1302 timekeeping and NVRAM chip loses power, such as if the lithium
battery goes dead.
When run, assorted system settings will be displayed. If this is the first time the
NVRAM has been powered up since losing battery power, defaults will be dis-
played. When finished editing the settings, make sure you press /textttEscape
instead of Return to make sure the settings are saved. The options and possible
settings are discussed below:
A. CPU Speed
One may choose to run the CPU at full or half speed.
Default is full speed.
B. Additional Memory Waits
70-nanosecond SRAM parts are necessary in order to use zero additional mem-
ory wait states. 70-nanosecond parts are provided in the kit, so it's okay to pick
0.
Default is 2 additional wait states.
C. Additional I/O Waits
The IO controller chip requires at least two additional wait states. Unpredictable
IO errors will result if fewer than two are used.
Default is 3 additional wait states.
D. Console Data Rate
Speeds of 300, 600, 1200, 2400, 4800, 9600, 19200, and 38400 bits per second
are available. BPS rates are determined by dividing the CPU clock pulses.
If you mess this up and forget what speed you set the P112 console to, simply
turn off power to the board, remove the jumper at P11, wait a few seconds,
replace the jumper, then turn the machine back on.
Default is 9600 bits per second. There are always 8 data bits, no parity bit, and
one stop bit. In shorthand, 9600,8N1.
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