4816 16K x 1 dynamic RAM (+5 V only) pinout
DIP-16. 16K x 1 dynamic RAM, single +5 V supply.
Single +5 V 16K x 1 parts (Acorn fitted 4816AP-3 and others); not 4116s, which need +12 and -5 V. The 6845 refreshes them by scanning the screen, so the RAM only works once the CPU has programmed the CRTC. Move link S25 to test one bank at a time (SM 6.3). Mixing makes after an A to B upgrade (Fujitsu with Mostek or Hitachi) causes timing faults (SM 6.4). On the Model B (IC53-IC68): two banks of eight make 32 KB; DIN and DOUT are paralleled per bit, /WE is the R/W line, /RAS is common to all 16 chips through R106 and pulses at 4 MHz, and CAS 0 / CAS 1 select the lower and upper 16K.
Open the interactive 4816 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | NC | nc | Not connected on the 4816 (pin-1 refresh /RFSH on the Mostek MK4516). UNVERIFIED |
| 2 | DIN | data | Data in. |
| 3 | /WE | ctrl | Write enable: low = write. |
| 4 | /RAS | ctrl | Row address strobe. |
| 5 | A0 | addr | Multiplexed address 0. |
| 6 | A2 | addr | Multiplexed address 2. |
| 7 | A1 | addr | Multiplexed address 1. |
| 8 | VCC | power | +5 V. |
| 9 | NC | nc | Not used on the BBC board (a 4116 has its +5 V VCC here and +12 V VDD on pin 8: do not fit 4116s). UNVERIFIED |
| 10 | A5 | addr | Multiplexed address 5. |
| 11 | A4 | addr | Multiplexed address 4. |
| 12 | A3 | addr | Multiplexed address 3. |
| 13 | A6 | addr | Multiplexed address 6. |
| 14 | DOUT | data | Data out (three-state). |
| 15 | /CAS | ctrl | Column address strobe. |
| 16 | VSS | ground | Ground. |
Fitted in
- BBC Micro Model B IC53-IC68 (bank CAS 0 and CAS 1)