MB87P2020 Datasheet, PDF (341/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

Hints and Restrictions
2.2 Command FSM
During emulation for Jasmine development a hang-up of the command FSM has been observed while the
commands GetPA and NoOp have been executed within a loop. This hang-up has never been observed for
Lavender.
Based on this emulation result the command FSM for Jasmine has been redesigned in order to avoid this
problem in the future.
At the present time it can not securely excluded that the timing gap problem is NOT present on Lavender.
Therefore further investigation and verification is necessary to check the Lavender behaviour with respect
to this problem.
Table 2-3 gives an overview and a classification about the described problem.
Table 2-3: Overview for timing gap problem
Subject
Description
Description
A command FSM hang up has been observed for an intermediate version^a
of Jasmine.
Classification
HW limitation
Effects without
workaround
The command execution is stopped at next command. Only a hardware
reset can terminate this state.
Solution/Workaround
For Jasmine this problem is fixed.
For Lavender it is not clear whether this problem occurs. Therefore further
investigation is necessary.
Concerned devices
MB87J2120 (Lavender)
fixed for MB87P2020 (Jasmine)
fixed for MB87P2020-A (Jasmine redesign)
Testcase
EMDC: ULB.1
a. The term ’intermediate’ means a RTL version between Lavender and Jasmine.
2.3 GPU mastertiming synchronization
For Lavender the internal GPU mastertiming signal (master switch for GPU) is not synchronized to display
clock domain (output pixel clock) properly.
If the pixel clock runs asynchronous to core clock (e.g. external pixel clock) and the flag MTIMON_ON is
switched on display output may hang afterwards.
In order to avoid this problem no asynchronous display clock should be used. Asynchronous display clock
can either be an external display clock or an internal clock derived from another clock than core clock. With
other words core and display clock should have the same clock source. See chapter B-1 (Clock Unit (CU))
description in hardware manual for further details about Lavender’s clock concept.
For Jasmine this problem is solved.
Table 2-4 gives an overview and a classification about the described problem.
Table 2-4: Overview for GPU mastertiming
Subject
Description
Description
If an asynchronous display clock (compared to core clock) is used, turning
on/off the GPU with help of MTIMON_ON can cause the display output to
hang.
Restrictions
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