AN2408 Freescale Semiconductor / Motorola, AN2408 Datasheet - Page 12

• Manufacturer Part Number: AN2408
• Description: Examples of HCS12 External Bus Design A Companion Note to AN2287/D
• Manufacturer: Freescale Semiconductor / Motorola

Example #4 — Byte-Wide SRAM Interface (Narrow Mode) XCS/ECS Gated
Figure 11
is divided into two 8-bit accesses by the MCU. Notice that the ECS signal is negated between memory
accesses.
Figure 10
to x +16 pages as this is an 8-bit memory and only ADDR19 is used for decoding
Figure 12
timing tool.
12
illustrates a sample timing analysis for
is a logic analyzer trace showing the narrow mode access with ECS gating. This word access
details memory implementation of Example #4. Notice the external memory will mirror from x
Figure 11. Expanded Narrow Word Access with ECS/XCS
Examples of HCS12 External Bus Design, Rev. 2
Figure
9. It was generated with a commercially available
Freescale Semiconductor