On 17/12/2016 14:28, Tony Duell wrote:
On Sat, Dec 17, 2016 at 2:02 PM, Adrian Graham <wit...@binarydinosaurs.co.uk> wrote:
Thanks all, the pinouts are matching the LS9x counters so I just need to trace more lines to hopefully narrow it down. Pins 6 and 7 are definitely inputs so you're right Tony, the reset must come from elsewhere. One of the outputs is confusing though since it appears to come FROM 5V via a resistor,
What value resistor? It is possible that whatever it is driving needs a swing to +5V, rather than just a TTL high level. Adding a pull-up resistor is a way to kludge this.
The CLOCK line on a Z80 is usually arranged like this, with a 330R (or thereabouts) pullup.
-- Pete Pete Turnbull
