Color RAM 2114

Employed in: C64 (as of version 469 Rev B included in the MMU), SX64

The 2114 is a 0.5k x 4 SRAM chip which is employed in the C64 as color RAM.

Technical data

Capacity: 0.5kB
4 bit data bus
10 bit address bus

Pinout

Fig.: Color RAM

Signal description

Pin(s) | Signal    | Dir | Note
-------+-----------+-----+-----------------------------------------
 1-7   | A6 - A2   | I/O | Bits 6 to 2 of the address bus.
  8    | /CS       |  I  | Chip Select.
  9    | GND       |  -  | Ground (0V).
 10    | /WE       |  I  | Write Enable. 0=RAM can be written to
 11-14 | D4 - D1   | I/O | Data bits.
 15-17 | A9 - A7   | I/O | Bits 9 to 7 of the address bus.
 18    | Vcc       |  -  | Supply voltage (5V).

Technical info

The 2114 gets coupled/decoupled by the 4066 in U16 (old board) or U21 (new board), respectively.

In newer revisions of the new boards, the color RAM is included in the MMU.

Programming info

In the Commodore 64, this chip is mapped to $d800-dbff. The first 1000 bytes (or nibbles, to be precise) store the color of the 1000 characters in text mode (which is 40x25). Note that only the low 4 bits make up the color, the other 4 bits are "don't care", since the SRAM is only 4 bits wide.

Updated: November 24th, 1997
Created: November 21st, 1997
Status : NOT VERIFIED!