C8051F91X-C8051F90X 查看數據表（PDF） - Silicon Laboratories

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C8051F91X-C8051F90X

Single/Dual Battery, 0.9–3.6 V, 16–8 kB, SmaRTClock, 12/10-Bit ADC MCU

Silicon Laboratories 

C8051F91x-C8051F90x

13.1.2. Flash Erase Procedure

The Flash memory is organized in 512-byte pages. The erase operation applies to an entire page (setting

all bytes in the page to 0xFF). To erase an entire Flash page, perform the following steps:

1. Save current interrupt state and disable interrupts.

2. Set the PSEE bit (register PSCTL).

3. Set the PSWE bit (register PSCTL).

4. Write the first key code to FLKEY: 0xA5.

5. Write the second key code to FLKEY: 0xF1.

6. Using the MOVX instruction, write a data byte to any location within the page to be erased.

7. Clear the PSWE and PSEE bits.

8. Restore previous interrupt state.

Steps 4–6 must be repeated for each 512-byte page to be erased.

Notes:

1. To maintain code compatibility with the ‘F93x-’F92x product family, the erase procedure should be performed

on two consecutive 512-byte sections of memory at a time. This allows the same software to run on devices

with 1024-byte or 512-byte Flash pages. Using this technique, devices with 1024-byte Flash pages will have

each Flash page erased twice.

2. Flash security settings may prevent erasure of some Flash pages, such as the reserved area and the page

containing the lock bytes. For a summary of Flash security settings and restrictions affecting Flash erase

operations, please see Section “13.3. Security Options” on page 134.

3. 8-bit MOVX instructions cannot be used to erase or write to Flash memory at addresses higher than 0x00FF.

13.1.3. Flash Write Procedure

A write to Flash memory can clear bits to logic 0 but cannot set them; only an erase operation can set bits

to logic 1 in Flash. A byte location to be programmed should be erased before a new value is written.

The recommended procedure for writing a single byte in Flash is as follows:

1. Save current interrupt state and disable interrupts.

2. Ensure that the Flash byte has been erased (has a value of 0xFF).

3. Set the PSWE bit (register PSCTL).

4. Clear the PSEE bit (register PSCTL).

5. Write the first key code to FLKEY: 0xA5.

6. Write the second key code to FLKEY: 0xF1.

7. Using the MOVX instruction, write a single data byte to the desired location within the 1024-

byte sector.

8. Clear the PSWE bit.

9. Restore previous interrupt state.

Steps 5–7 must be repeated for each byte to be written.

Notes:

1. Flash security settings may prevent writes to some areas of Flash, such as the reserved area. For a summary

of Flash security settings and restrictions affecting Flash write operations, please see Section “13.3. Security

Options” on page 134.

2. 8-bit MOVX instructions cannot be used to erase or write to Flash memory at addresses higher than 0x00FF.

13.2. Non-volatile Data Storage

The Flash memory can be used for non-volatile data storage as well as program code. This allows data

such as calibration coefficients to be calculated and stored at run time. Data is written using the MOVX

write instruction and read using the MOVC instruction. MOVX read instructions always target XRAM.

An additional 512-byte scratchpad is available for non-volatile data storage. It is accessible at addresses

0x0000 to 0x01FF when SFLE is set to 1. The scratchpad area cannot be used for code execution.

Rev. 1.0

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