Proposed patch for issue #29 (related to RCM4110 Rev F hardware) #30
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The are multiple reasons to enable early /OE in MTCR, so do so whenever necessary and don't disable it for any reason.
Other products that enable early /OE do so before enabling the clock doubler or the spectrum spreader. The RCM4110 doesn't use a clock doubler and can be configured with a disabled spectrum spreader. Yet it may still need to have early /OE enabled to meet timing requirements of 55ns flash used in RCM4110 (part 20-101-1093) Rev F. This change enables early /OE before writing to MB0CR and disabling wait states. It also ensures we enable the feature even in firmware with a disabled spectrum spreader.
tomlogic
commented
Apr 6, 2021
| @@ -122,8 +122,6 @@ _enableClockModulation:: | |||
| bool hl | |||
| #if ENABLE_SPREADER == 0 // spreader disabled | |||
| xor a | |||
| ld (MTCRShadow), a | |||
| ioi ld (MTCR), a // normal /OE0 and /OE1 timing | |||
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Even with the spreader disabled, we should keep the "early /OE" setting on products that have enabled it.
| ld a, 0x0C | ||
| ioi ld (MTCR), a | ||
| #endif | ||
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This change enables "early /OE" on the RCM4110 before reaching code that configures MB0CR for 0 wait states, and therefore will access the RCM4110's 55ns flash at full speed.
| ioi ld (MTCR), a ; first, update /OE0, /OE1 early output enable | ||
| ld (MTCRShadow), a | ||
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| .notEarlyOutputEnable: |
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This change leaves MTCR unmodified when the clock doubler isn't enabled -- allowing the RCM4110 setting from line 1881 to remain in place.
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This branch has the proposed patch to resolve issue #29, and will become part of the
masterbranch once approved for release.