diff options
Diffstat (limited to 'src/mess/drivers/tispeak.c')
-rw-r--r-- | src/mess/drivers/tispeak.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/mess/drivers/tispeak.c b/src/mess/drivers/tispeak.c index 5bf841e7825..100fdd14e5c 100644 --- a/src/mess/drivers/tispeak.c +++ b/src/mess/drivers/tispeak.c @@ -18,9 +18,10 @@ #include "tispeak.lh" // The master clock is a single stage RC oscillator into TMS5100 RCOSC: -// C is 68pf, R is a 50kohm trimpot wich is set to 33.6kohm. CPUCLK is this/2, ROMCLK is this/4. +// In an early 1979 Speak & Spell, C is 68pf, R is a 50kohm trimpot which is set to around 33.6kohm +// (measured in-circuit). CPUCLK is this osc freq /2, ROMCLK is this osc freq /4. // The typical osc freq curve for TMS5100 is unknown. Let's assume it is set to the default frequency, -// which is 640kHz according to the TMS5100 documentation. +// which is 640kHz for 8KHz according to the TMS5100 documentation. #define MASTER_CLOCK (640000) |