MB87P2020 Datasheet, PDF (343/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

Hints and Restrictions
7
addr0 +0
31
0
Byte 0 Byte 1 Byte 2 Byte 3
0
+1
+2
+3
addr1 +0
+1
Figure 2-1: Address offsets in byte addressed memory and its mapping to Jasmine/Lavender in-
ternal registers
In C-API the described workaround is already implemented. Within API read accesses from address offset 2
and 3 are limited to registers FLNOM_IFF and FLNOM_OFE. These accesses are implemented as 32-Bit
read accesses.
Table 2-6 gives an overview and a classification about the described problem.
Table 2-6: Overview for read limitation in 16Bit data mode
Subject
Description
Classification
Effects without
workaround
Solution/Workaround
Concerned devices
Testcase
Description
Read access from addr0+2 or addr0+3 does not work reliable.
HW limitation
Halfword and byte read access from addr0+2 or addr0+3 may deliver
wrong values in 16Bit data mode (MODE[2]=0).
Read data from addr0+0 or addr0+1 before reading from addr0+2 or
addr0+3.
OR
Limit read accesses to 32Bit read accesses only.
All C-API functions which have to read back values implement this worka-
round already.
MB87J2120 (Lavender)
MB87P2020 (Jasmine)
MB87P2020-A (Jasmine redesign)
EMDC: CTRL.1 (I/O march) and IPA.1 in 16Bit data mode.
Restrictions
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