AN694 SILABS [Silicon Laboratories], AN694 Datasheet - Page 2

• Manufacturer Part Number: AN694
• Description: WRITING TO FLASH FROM FIRMWARE ON SiM3XXXX DEVICES
• Manufacturer: SILABS [Silicon Laboratories]

AN694
3. Flash Essentials
Different device series have many similarities for Flash, including page sizes, lock bits, and the instructions used to
read and write to Flash. The main differences are the amount of Flash available, how the voltage supply monitor is
enabled, how the voltage supply monitor is enabled as a reset source, and how registers are modified to allow
Flash writes and erases. Although the core stalls during Flash write and erase operations, peripherals (USARTn,
SARADCn, TIMERn, etc.) remain active. Interrupts posted during a Flash write or erase operation are held until the
Flash operation has completed, after which they are serviced in priority order.
3.1. Flash Organization
The Flash memory on most devices is organized into a set of 1024-byte pages. See the Memory Organization
chapter of the device reference manual for specific information. Figures 1, 2, 3, and 4 show the Flash organization
for the SiM3Uxxx devices.
2
0x1FFF_FFFF
0x1FFF_FFFF
0x0003_FFFF
0x0001_FFFF
0x0003_FFFF
0
0x0004_0000
0x0004_0000
0x0000_0000
X
0000_0000
Figure 1. SiM3U16x Flash Memory Map (256 kB)
Figure 2. SiM3U15x Flash Memory Map (128 kB)
Rev. 0.1
Lock Word
Lock Word
Reserved
Reserved
Reserved
Flash
Flash
0x0003_FFFC
0x0003_FFFC