Synertec C43013 (HP 1818-1250) – ROM paired with C43012

Definition

The Synertec C43013 is a ROM (read-only memory) used as a firmware component in HP systems, designed to operate together with the Synertec Synertec C43012. In practice, the C43013/C43012 pair provides non-volatile contents that the system reads at startup and during operation, typically for resident routines, configuration tables, and internal operating logic.

The associated HP part number for the C43013 is 1818-1250.

Functional relationship with the C43012: why two ROMs

The fact that the C43013 “works together” with the C43012 indicates that the firmware is distributed across two ROM ICs. In architectures of this class, the two ROMs may be used for:

Separating the contents into blocks (for example main program and support/diagnostics functions).

Interleaved or “paired” organization to match the bus and system timing (for example even/odd byte handling or logical splitting of the firmware).

The retrieved information explicitly confirms the C43013 ↔ C43012 pairing and the HP part number, but it does not provide a memory map or a complete pinout.

HP part number and bill-of-material identification

In service/spares contexts, the code 1818-1250 is often the most useful reference for:

Searching the component in documentation and spare-part inventories,

Checking compatibility across firmware revisions/steps,

Ensuring correct replacement as a pair (C43013 + C43012) rather than as a single isolated IC.

Indicated application context

The C43013 is associated with HP instrumentation; in the referenced object/category pages it is linked, as a ROM component, to a class of instruments where the HP 5335A Universal Counter is cited as an example context/category.

Package and practical replacement constraints

The consulted pages do not explicitly state the package of the C43013 (field not populated). In practice, before ordering or replacing the component it is advisable to verify directly:

Full markings on the chip (codes, possible date codes),

Physical format and pin pitch on the board,

Presence of a socket and contact condition (oxidation/looseness).

Sketch of the most important connections

                 address bus (A0..An) + control signals
        ┌──────────────────────────────────────────────────────┐
        │                     CPU / Controller                 │
        │                                                      │
        │  address ───────────────┬───────────────┐           │
        │  control (/CE,/OE, etc.) ├─────┐         │           │
        └──────────────────────────┘     │         │           │
                                          ▼         ▼
                               ┌────────────────┐  ┌────────────────┐
                               │  Synertec      │  │  Synertec      │
                               │  C43012        │  │  C43013        │
                               │  ROM (HP       │  │  ROM (HP       │
                               │  1818-1249)    │  │  1818-1250)    │
                               └───────┬────────┘  └───────┬────────┘
                                       │                   │
                                       └────── data bus ───┘
                                              (D0..D7)

Table 1 – Identification data and specifications

Table 2 – Operational and design considerations