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Rev. 1.00
507 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
24 Peripheral Direct Memory
Access (PDMA)
24 Peripheral Direct Memory
Access (PDMA)
Functional Description
AHB Master
The PDMA is an AHB master connected to other AHB peripherals such as the Flash Memory, the
SRAM memory and the AHB-to-APB bridge through the bus-matrix. The CPU and PDMA can
access different AHB slaves at the same time via the bus-matrix.
PDMA Channel
There are 6 unidirectional PDMA channels used to support data transfer between the peripherals
and the memory. The configuration and operation of each PDMA channel is independent. For
a bidirectional transfer application, two PDMA channels are required. Each PDMA channel is
designed to support the dedicated multiple peripherals with the same registers. Therefore, one
PDMA channel only can service one peripheral at the same time. The related registers of the
PDMA channel are limited to be accessed with 32-bit operation, otherwise a system hard fault
event will occur.
PDMA Request Mapping
The multiple requests from the peripherals (ADC, SPI, I
2
C, USART and so on) are simply logically
ANDed before entering the PDMA, which means that only one request must be enabled at a time
in each PDMA channel. Refer to Figure 184 – PDMA request mapping architecture and detailed
peripheral IP requests mapping table is shown as the Table 62. The peripheral DMA requests can
be independently activated/de-activated by programming the DMA control bit in the registers of
the corresponding peripheral.
Channel 0
Channel n
Channel 1
Channel 2
PDMA
Request
High priority
Low priority
SWTRIG Enable
CH0 S/W REQ
CHn S/W REQ
SWTRIG Enable
CH0 H/W REQ
0
1
0
1
CHn H/W REQ
IP1
IPn
IPx
IPy
Peripheral request signals
Figure 184. PDMA Request Mapping Architecture