AT32F421
Series Reference Manual
2022.11.11
Page 3
Rev 2.02
Clock sources ............................................................................. 45
System clock ............................................................................... 46
Peripheral clock .......................................................................... 46
Clock fail detector ....................................................................... 47
Auto step-by-step system clock switch .......................................... 47
Internal clock output .................................................................... 47
Interrupts .................................................................................... 47
Reset .......................................................................................... 47
System reset ............................................................................... 47
Battery powered domain reset ...................................................... 48
CRM registers ............................................................................. 48
Clock control register (CRM_CTRL) .............................................. 49
Clock configuration register (CRM_CFG) ...................................... 50
Clock interrupt register (CRM_CLK INT) ........................................ 51
APB2 peripheral reset register (CRM_APB2RST) .......................... 52
APB1 peripheral reset register1 (CRM_APB1RST) ........................ 53
AHB peripheral clock enable register (CRM_AHBEN) .................... 53
APB2 peripheral clock enable register (CRM_APB2EN) ................. 54
APB1 peripheral clock enable register (CRM_APB1EN) ................. 55
Battery powered domain control register (CRM_BPDC) .................. 56
Control/status register (CRM_CTRLSTS) ...................................... 56
AHB peripheral reset register (CRM_AHBRST) ............................. 57
PLL configuration register (CRM_PLL) .......................................... 57
Additional register (CRM_MISC1) ................................................. 58
Additional register (CRM_MISC2) ................................................. 59
Embedded Flash memory controller (FLASH) ............................... 60
FLASH introduction ...................................................................... 60
Flash memory operation ............................................................... 62
Unlock/lock ................................................................................. 62
Erase operation ........................................................................... 62
Programming operation................................................................ 64
Read operation ........................................................................... 65
Main Flash memory extension area ............................................... 65
User system data area ................................................................. 66