Interfacing to old ttl chips

[jmcdougall]

I am working through a computer copnversion replacing a 6502 and its pio chips with a superpro. I need to tap in to i/o that is based on uln chips (5V) can I use this
https://www.amazon.com/HiLetgo-TXS0108E ... NrPXRydWU=

To convert the 3.3v i/o on the superpro to 5v logic required by the uln chips?
I am powering the superpro at 5V

[basicchip]

If you are using ULN2003A chips, you can drive those directly from the SuperPRO IO

They turn on at 2.4-2.7 V (from the spec sheet)

LPC1756 outputs 4mA (from the NXP spec sheet)

I have driven these directly before.

[jmcdougall]

Mostly uln2003, some 4068s, and 40438, uln2009. Thereh is a DAC08 that is used as a D/A that feed one side of 4 LM339 with a reference voltage for the comparison but I should be able to go straight from the analog out of the superpro to the one input of the LM339s. The other input side of the LM339s are thermistor voltage inputs.The analog outs from the LM339s are fed into analog inputs. There are 10K to ground dropping resisters on each of the analog input lines i.e. output from the LM339s. 0 to 3v input = cold 0v input = on temp or too Hot. I suspect that once the input goes to 0v, the comparative voltage from the output is varied by steps to determine if Ok or too hot and by how much.

[basicchip]

You really need to be more specific about the part numbers. The 4068 comes in lots of varieties, the CD4068 normally is powered by 5V and requires inputs higher than 3.3V to switch, so would require buffering or pullups.

I'm not sure what a ULN2009 is (a typo maybe). Same goes for 40438.

Spec sheets are readily available at Digikey or Mouser, or the chip vendor.

[jmcdougall]

40438 is probably the 4043B

Quite possible the ULN2009 is a hand written slurred uln2003

ther are several 4069s although they may not be required going forward. I am assuming given the era (early eighties) that these are all CD40xx versions - i.e. 5V

There are 12v and 8v as well as 5v running around on the board. Most of the solenoids and the rotate motor are 12V. 8v seems to be used on the analog side (sensors) while the 5v is the digital supply. 8v and 12v come from the main PS board. The 5v has a separate large power regulator board.

[basicchip]

Old CMOS CD devices require a Vih to switch high more than 3.3V so would either have to buffer those lines or replace them with CMOS devices that have TTL thresholds most CDxxxx devices have a 74HCTxxx equivalent. Consult the spec sheet.