EZ80190AZ050SC00TR Zilog, EZ80190AZ050SC00TR Datasheet - Page 152

• Manufacturer Part Number: EZ80190AZ050SC00TR
• Description: IC EZ80 ACCLAIM 50MHZ 100LQFP
• Manufacturer: Zilog

Specifications of EZ80190AZ050SC00TR

• Processor Type: eZ80
• Features: High Speed, Single-Cycle Instruction-Fetch
• Speed: 50MHz
• Voltage: 3.3V
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

DMA Channel Priorities
DMA Interrupts
DMA Control Registers
Table 76. DMA Registers
PS006614-1208
Name
DMA0_SAR_L
DMA0_SAR_H
DMA0_SAR_U
In all operating mode combinations, DMA Channel 0 is prioritized higher than DMA
Channel 1. If Channel 0 is configured for BURST mode operation, Channel 0 completes
its entire block transfer before Channel 1 begins its transfer.
When both channels are configured for CYCLE-STEAL mode, the 2 DMA channels alter-
nate stealing execution cycles from the CPU. First, DMA Channel 0 performs a cycle-steal
single-byte transfer then releases the bus to the CPU for the next 8 clock cycles. Then,
DMA channel 1 requests the bus and gains access to pass one of its bytes. After DMA
channel 1 completes the transfer of its byte, control is returned to the CPU for another
8 clock cycles. This process repeats until one or both of the DMA channels complete the
transfer of all required bytes.
If DMA channel 0 is programmed in CYCLE-STEAL mode and DMA channel 1 is pro-
grammed in BURST mode, DMA channel 1 is not allowed to transfer its data until DMA
channel 0 completes its entire transfer.
Each DMA controller can generate an interrupt request to the CPU when its memory
transfer is complete. The DMA interrupts are enabled by setting bit 6 in the DMA Control
register (either DMA0_CTL or DMA1_CTL) to 1. The default operation is for the DMA
interrupts to be disabled. Each DMA channel is capable of generating an interrupt when its
16-bit data byte transfer counter register reaches its terminal count of
rupts are cleared by resetting the DMA_EN bit field in the DMA Control registers to dis-
able the DMA channel that is generating the input. Clearing the interrupt enable bit
(DMAx_CTL[6] = IRQ_DMA) does not clear the interrupt to the CPU after it is set.
Table 76
accessed by the CPU using I/O instructions.
Description
DMA0 Source Address Low Byte register
DMA0 Source Address High Byte register
DMA0 Source Address Upper Byte register
lists the control registers used by the DMA controller. These registers are
Access
CPU
R/W
R/W
R/W
Direct Memory Access Controller
Product Specification
Reset
Value
0000h
XX
XX
XX
. The inter-
Register
Address
eZ80190
EEh
EFh
F0h
142