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Rev. 1.00
42 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
3 System
Architecture
Embedded Flash Memory
The HT32F54231/HT32F54241/HT32F54243/HT32F54253 device series provide an up to 128
KB on-chip Flash memory which is located at address 0x0000_0000. It supports byte, half-
word and word access operations. Note that the Flash memory only supports read operations for
the bus access. Any write operations to the Flash memory will cause a bus fault exception. The
Flash memory has up to 128 pages. Each page has a memory capacity of 1 KB and can be erased
independently. A 32-bit programming interface provides the capability of changing bits from 1 to 0.
A data storage or firmware upgrade can be implemented using several methods such as In System
Programming (ISP), In Application Programming (IAP) or In Circuit Programming (ICP). For
more information, refer to the Flash Memory Controller section.
Embedded SRAM Memory
The HT32F54231/HT32F54241/HT32F54243/HT32F54253 device series contain an up to 16 KB
on-chip SRAM which is located at address 0x2000_0000. It supports byte, half-word and word
access operations.
AHB Peripherals
The address of the AHB peripherals ranges from 0x4008_0000 to 0x400F_FFFF. Some peripherals
such as Clock Control Unit, Reset Control Unit and Flash Memory Controller are connected to the
AHB bus directly. The AHB peripherals clocks are always enabled after a system reset. Access to
registers for these peripherals can be achieved directly via the AHB bus. Note that all peripheral
registers in the AHB bus support only word access.
APB Peripherals
The address of APB peripherals ranges from 0x4000_0000 to 0x4007_FFFF. An APB to AHB
Bridge provides access capability between the CPU and the APB peripherals. Additionally, the
APB peripheral clocks are disabled after a system reset. Software must enable the peripheral clocks
by setting up the APBCCRn register in the Clock Control Unit before accessing the corresponding
peripheral register. Note that the APB to AHB Bridge will duplicate the half-word or byte data to
word width when a half-word or byte access is performed on the APB peripheral registers. In other
words, the access result of a half-word or byte access on the APB peripheral register will vary
depending on the data bit width of the access operation on the peripheral registers.