General
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General Information |
The COSMAC 1804 was RCA’s first single chip microcomputer. The 1804 was an 1802 with on chip 2KB of mask programmable ROM and 32 bytes of RAM added. It is almost pin compatible with the 1802 except pin 16 differs on the 1802 it is Vcc and on the 1804 it is EMS. The 1804 is software compatible with the 1802 and added 22 instructions. |
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Production |
1976 |
| Designers | Lead Designer: Joe Weisbecker, Team Lead: Jerry Herzog |
Architecture
| Type | Data Word | Address Space | Max Clock | Instruct- ions | Assists | Reg’s GP | Reg’s Math | Reg’s Index | IO Ports | Stack | Interrupts | Memory |
| MCU, CMOS | 8-bit | 64K | 4Mhz and 8Mhz | 113 | NA | 16×16-bit or 32×8-bit | 1 | NA | 8 | Ext RAM | 1 Level | 2KB ROM, 64B RAM |
Packages
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Chip Name |
Package |
On-Chip Identification |
Picture |
General Comments |
| CDP1804D | white ceramic, silver lid, 40 gold side braised pins | CDP1804D | Standard operating range: 4V to10.5V. The ceramic “D” versions have an operating temperature range of -55o to 120oC | |
| CDP1804CD | gray ceramic, silver lid, 40 gold side braised pins | CDP1804CD | “C” suffix versions have a lower voltage range: 4V to 6.5V. Max clock is limited to 4Mhz. | |
| CDP1804AD | white ceramic, silver lid, 40 gold side braised pins | CDP1804AD | ||
| CDP1804ACD | white ceramic, silver lid, 40 gold side braised pins | CDP1804ACD | ||
| CDP1804E | black plastic, 40 tin leads | CDP1804E | The plastic “E” versions have an operating temperature range of -40o to 85oC, | |
| CDP1804CE | black plastic, 40 tin leads | CDP1804CE | ||
| CDP1804AE | black plastic, 40 tin leads | CDP1804AE | ||
| CDP1804ACE | black plastic, 40 tin leads | CDP1804ACE | ||
| CDP1804PCE | I have found little information about this chip. It appears to be a microprocessor version of the 1804 with no RAM or ROM |
Related Chips
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Related Chips |
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Second Sources |
None |
| Support Chips | 1852 (8-bit I/O Port), 1854 (UART), 1856 (4-bit memory buffer), 1857 (4-bit I/O buffer) |