SH7764 Datasheet, PDF (398/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series

Section 11 Memory Controller Unit (MCU)
The priority is determined hierarchically according to the priority level, round-robin scheduling
for the modules with the same priority level, and sub-round-robin scheduling for the modules with
the same priority level, in this order. The following describes each determination.
1. Determination according to the priority level
The priority is fixed: level 0 > level 1 > level 2 > level 3.
2. Determination according to the level-1 round-robin scheduling
The priority is determined according to the round-robin scheduling for the level-1 modules.
After reset: LCDC > pixel bus module
After the LCDC has been selected: Pixel bus > LCDC
After the pixel bus has been selected: LCDC > pixel bus
Note that the pixel bus refers to the modules selected according to the level-1 pixel bus sub-
round-robin scheduling.
3. Determination according to the level-1 pixel bus sub-round-robin scheduling
When this determination is selected, the priority is also determined according to the round-
robin scheduling for the level-1 pixel bus modules.
After reset: VDC2 (layer 1) > VDC2 (layer 2) > VDC2 (layer 3) > VDC2 (layer 4)
After the VDC2 (layer 1) has been selected: VDC2 (layer 2) > VDC2 (layer 3) > VDC2 (layer
4) > VDC2 (layer 1)
After the VDC2 (layer 2) has been selected: VDC2 (layer 3) > VDC2 (layer 4) > VDC2 (layer
1) > VDC2 (layer 2)
After the VDC2 (layer 3) has been selected: VDC2 (layer 4) > VDC2 (layer 1) > VDC2 (layer
2) > VDC2 (layer 3)
After the VDC2 (layer 4) has been selected: VDC2 (layer 1) > VDC2 (layer 2) > VDC2 (layer
3) > VDC2 (layer 4)
4. Determination according to the level-2 or level-3 round-robin scheduling
The priority is determined according to the round-robin scheduling for the level-2 or level-3
modules. Either priority level 2 or 3 can be given to the devices separately through the
arbitration mode register.
When the same priority level is assigned to more than one device, the priority is determined
according to the round-robin scheduling for each level.
The priority of the devices with the same priority level is as follows:
After reset: SuperHyway > pixel bus > LCDC
Note that the pixel bus refers to the devices selected according to the level-2 or level-3 pixel
bus sub-round-robin scheduling.
After the pixel bus has been selected: LCDC > SuperHyway > pixel bus
After the LCDC has been selected: SuperHyway > pixel bus > LCDC
Rev. 1.00 Nov. 22, 2007 Page 342 of 1692
REJ09B0360-0100