On-Chip Static Ram - Philips LPC2194 User Manual

Philips Semiconductors Preliminary User Manual
ARM-based Microcontroller LPC2119/2129/2194/2292/2294

ON-CHIP STATIC RAM

The LPC2119/2129/2194/2292/2294 provide a 16 kB static RAM memory that may be used for code and/or data storage. The
SRAM supports 8-bit, 16-bit, and 32-bit accesses.
The SRAM controller incorporates a write-back buffer in order to prevent CPU stalls during back-to-back writes. The write-back
buffer always holds the last data sent by software to the SRAM. This data is only written to the SRAM when another write is
requested by software (the data is only written to the SRAM when software does another write). If a chip reset occurs, actual
SRAM contents will not reflect the most recent write request (i.e. after a "warm" chip reset, the SRAM does not reflect the last
write operation). Any software that checks SRAM contents after reset must take this into account. Two identical writes to a
location guarantee that the data will be present after a Reset. Alternatively, a dummy write operation before entering idle or
power-down mode will similarly guarantee that the last data written will be present in SRAM after a subsequent Reset.
Introduction 19 May 03, 2004