OBD0 5128 SRAM Technical Reference
Technical overview of the 2K byte 5128 SRAM chip used in Honda OBD0 ECUs, including memory mapping and addressing specifications.
The 5128 chip found in OBD0 ECUs is a 2K byte SRAM component used for external data storage.
Memory Mapping
The 5128 SRAM is mapped into the ECU memory space starting at 1000h. Any external communication using the MOVX A,@DPTR instruction where the Data Pointer (DPTR) falls within the range of 1000h to 1FFFh will address this SRAM chip.
Important
Accessing memory addresses outside of the
1000hâ1FFFhrange will not interact with the 5128 SRAM chip.
Memory Usage
The data stored within this XRAM space is critical for ECU operation, including sensor data buffering and real-time calculation variables.
| Address Range | Description |
|---|---|
1000h - 1FFFh |
5128 SRAM Address Space |
For specific details regarding the data stored within this memory range, refer to the OBD0 PM6/PM7 RAM Locations0 documentation.