Pinout diagram
Used in Retro Machine Hubs
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Summary specifications
Full pin reference
| Pin | Name | Group | Direction | Levels | Description |
|---|---|---|---|---|---|
| 1 | /OE (/G) | Control | Input | TTL, active low | Output Enable. Gates DQ1-DQ4 onto the bus during a read cycle. |
| 2 | DQ1 | Data Bus | Bidirectional | TTL | Bidirectional Data bit 1 (connects to D0 on the Low-Nibble chip, and D4 on the High-Nibble chip!). |
| 3 | DQ2 | Data Bus | Bidirectional | TTL | Bidirectional Data bit 2 (connects to D1 or D5). |
| 4 | /WE | Control | Input | TTL, active low | Write Enable input. |
| 5 | /RAS | Control | Input | TTL, active low | Row Address Strobe input. |
| 6 | A6 (A0) | Address Bus | Input | TTL | Multiplexed address input. |
| 7 | A5 (A1) | Address Bus | Input | TTL | Multiplexed address input. |
| 8 | A4 (A2) | Address Bus | Input | TTL | Multiplexed address input. |
| 9 | VCC (+5V) | Power | Power | +5 V | +5 V power supply (at the bottom-left corner Pin 9, just like 4116 Pin 9!). |
| 10 | A7 (NC on 4416) | Address Bus | Input | TTL | Address bit 7 on 4464 (64Kx4)! On a 16Kx4 4416 only 6 column bits are used; connecting A7 upgrades 2x 4416 (16KB) to 2x 4464 (64KB)! |
| 11 | A3 | Address Bus | Input | TTL | Multiplexed address input. |
| 12 | A2 | Address Bus | Input | TTL | Multiplexed address input. |
| 13 | A1 | Address Bus | Input | TTL | Multiplexed address input. |
| 14 | A0 | Address Bus | Input | TTL | Multiplexed address input. |
| 15 | DQ3 | Data Bus | Bidirectional | TTL | Bidirectional Data bit 3 (connects to D2 or D6). |
| 16 | /CAS | Control | Input | TTL, active low | Column Address Strobe input. |
| 17 | DQ4 | Data Bus | Bidirectional | TTL | Bidirectional Data bit 4 (connects to D3 on the Low-Nibble chip, and D7 on the High-Nibble chip!). |
| 18 | VSS (GND) | Ground | Power | 0 V | System ground (0 V at top-right Pin 18). |
Common uses and repair diagnostics
Instead of requiring eight 16-pin 1-bit-wide (x1) DRAMs to form an 8-bit byte, the 18-pin 4416 (16,384 x 4 bits = 8 KB per chip) and 4464 / 41464 (65,536 x 4 bits = 32 KB per chip) store a full 4-bit nibble (DQ1-DQ4) in each chip — so just TWO 18-pin chips form a complete 16 KB (2x 4416) or 64 KB (2x 4464) byte-wide memory bank! Even better, the 4416 and 4464 share the EXACT SAME 18-pin pinout (with Pin 5 and Pin 9 adding the extra address bit on the 4464), making 16KB-to-64KB upgrades on the Commodore 16, C116, Flat C128 8563 VDC, Atari 600XL, and Tandy CoCo 2 effortless!
2x 4416 (16 KB): Commodore 16, Commodore 116, Flat C128 8563 VDC Video RAM, Atari 600XL, Tandy CoCo 2 (16K), MSX2 (64K VRAM = 8x 4416).
2x 4464 / 41464 (64 KB): Commodore 64C shortboard (ASSY 250469 — U10 & U11), C128DCR 8568 VDC (64 KB VRAM), Atari XEGS, Tandy CoCo 2 (64K) & CoCo 3 (128K = 4x 4464), MSX2 (128K VRAM = 4x 4464).
- In any 2-chip 4416/4464 system (C64C ASSY 250469, C16, C116, Atari 600XL, CoCo 2), one chip handles the Low Nibble (D0-D3) and the other handles the High Nibble (D4-D7)!
- Flat C128 16KB -> 64KB 80-Column Video RAM Upgrade: Simply pull the two 4416 chips from sockets U22 and U23 and drop in two 4464 chips — the 8563 VDC already wires RA7 to Pin 10 on the PCB!