Global control

Table of content

• 1. Introduction
• 2. Registers
  • 2.1 GFX_CTRL
  • 2.2 GFX_STATUS
  • 2.3 GFX_IRQ

1. Introduction

This section describes the global control, status and interrupt flag registers.

2. Registers

2.1 GFX_CTRL

Address: 0x00		Global control register
15	14	13	12	11	10	9	8
res.			GPU_EN	res.	GFX_MODE

7	6	5	4	3	2	1	0
IE_GCMD_E	IE_GCMD_D	IE_GFIFO_O	IE_GFIFO_D	res.	IE_RCDONE	IE_RSTART	IE_RDONE

	•   GPU_EN	: Enable Graphic Processing Unit     0 = GPU is disabled     1 = GPU is enabled
	•   GFX_MODE	: Graphic Mode Configuration (bit-per-pixel)     000 = 1 bit-per-pixel     001 = 2 bit-per-pixel     010 = 4 bit-per-pixel     011 = 8 bit-per-pixel     others = 16 bit-per-pixel
	•   IE_GCMD_E	: GPU command error interrupt enable bit     0 = disable GPUCMD error interrupt     1 = enable GPUCMD error interrupt
	•   IE_GCMD_D	: GPU command done interrupt enable bit     0 = disable GPUCMD done interrupt     1 = enable GPUCMD done interrupt
	•   IE_GFIFO_O	: GPU FIFO overflow interrupt enable bit     0 = disable GPUFIFO overflow interrupt     1 = enable GPUFIFO overflow interrupt
	•   IE_GFIFO_D	: GPU FIFO done interrupt enable bit     0 = disable GPUFIFO done interrupt     1 = enable GPUFIFO done interrupt
	•   IE_RCDONE	: Screen refresh counter done interrupt enable bit     0 = disable REFR counter done interrupt     1 = enable REFR counter done interrupt
	•   IE_RSTART	: Screen refresh start interrupt enable bit     0 = disable REFR start interrupt     1 = enable REFR start interrupt
	•   IE_RDONE	: Screen refresh done interrupt enable bit     0 = disable REFR done interrupt     1 = enable REFR done interrupt

2.2 GFX_STATUS

Address: 0x08		Global status register
15	14	13	12	11	10	9	8
res.

7	6	5	4	3	2	1	0
res.	STA_GBUSY	res.	STA_GFIFO	res.			STA_RBUSY

	•   STA_GBUSY	: GPU busy status bit     0 = GPU is idle     1 = GPU is busy
	•   STA_GFIFO	: GPU FIFO status bit     0 = GPU FIFO is empty     1 = GPU FIFO is not empty
	•   STA_RBUSY	: Screen refresh busy status bit     0 = no screen refresh on going     1 = screen refresh currently on going

2.3 GFX_IRQ

Address: 0x00		Global control register
15	14	13	12	11	10	9	8
res.

7	6	5	4	3	2	1	0
IF_GCMD_E	IF_GCMD_D	IF_GFIFO_O	IF_GFIFO_D	res.	IF_RCDONE	IF_RSTART	IF_RDONE

	•   IF_GCMD_E	: GPU command error interrupt flag bit     0 = no GPU command error was detected     1 = GPU command error detected (write '1' to clear)
	•   IF_GCMD_D	: GPU command done interrupt flag bit     0 = GPU is IDLE or busy     1 = GPU command execution completed (write '1' to clear)
	•   IF_GFIFO_O	: GPU FIFO overflow interrupt flag bit     0 = GPU FIFO didn't overflow     1 = GPU FIFO overflow detected (write '1' to clear)
	•   IF_GFIFO_D	: GPU FIFO done interrupt flag bit     0 = GPU FIFO's last word was not read     1 = Last GPU FIFO word was read (write '1' to clear)
	•   IF_RCDONE	: Screen refresh counter done interrupt flag bit (see here)     0 = screen refresh counter is either 0 or still running     1 = screen refresh counter reached 0 (write '1' to clear)
	•   IF_RSTART	: Screen refresh start interrupt flag bit     0 = no new screen refresh started     1 = a new screen refresh started (write '1' to clear)
	•   IF_RDONE	: Screen refresh done interrupt flag bit     0 = no screen refresh has completed     1 = screen refresh completed (write '1' to clear)