Tronix
Experienced Member
Hello,
I want to introduce my simple DRAM memory tester based on PIC16F73 microcontroller. Possible replacement: PIC16F870, PIC16F873 and PIC16F876.
DRAM tester can test 4164 (565RU5 exUSSR) and 41256 (565RU7 exUSSR) DRAM IC. Tester has two working mode: "simple LEDs" and "advanced UART".
Todo:
1) static (6116, 6132, 6164) memory tests. Need add some extra component to board, such as tri-state 8 bit register for multiplexing address/data line. Need more space in PIC program EPROM, so PIC16F870 is't good choice. Low priority, because the static memory tests even in the Willem programmer.
2) Add exotic DRAM chips, such as very old MOS 40965DC or exUSSR 565RU3. This chips have tripple power lines: +5, -5 and +12V. It will lead to a complication of the circuit power supply. Low priority.
I want to introduce my simple DRAM memory tester based on PIC16F73 microcontroller. Possible replacement: PIC16F870, PIC16F873 and PIC16F876.
DRAM tester can test 4164 (565RU5 exUSSR) and 41256 (565RU7 exUSSR) DRAM IC. Tester has two working mode: "simple LEDs" and "advanced UART".
- simple LEDs: DRAM tester when power on autodetect inserted IC type (4164/41256). The LEDs blink four times. Then begin infinite loop testing; GREEN led turn off when pattern writing to DRAM and turn on when pattern reading from DRAM and comparing to etalon. If at some point the error occurred, RED led is turn on an still lighting until tester power off.
- advanced UART: For use this mode you need TTL compatible level UART cable, so MAX232 based is good choice, and COM port in your desktop. Advanced UART mode allows control refresh time, set manual IC type, set tests mode (patterns, running '1', running '0'), view errors and more. Still debuging, not avalible in current project stage.. UART display errors at current moment only. Serial settings is 9600bps-1N8.
Todo:
1) static (6116, 6132, 6164) memory tests. Need add some extra component to board, such as tri-state 8 bit register for multiplexing address/data line. Need more space in PIC program EPROM, so PIC16F870 is't good choice. Low priority, because the static memory tests even in the Willem programmer.
2) Add exotic DRAM chips, such as very old MOS 40965DC or exUSSR 565RU3. This chips have tripple power lines: +5, -5 and +12V. It will lead to a complication of the circuit power supply. Low priority.