W681307DG Datasheet, PDF (139/160 Pages) Winbond – USB1.1 CODEC Microprocessor Control Unit with 32KB Mask ROM and 4KB RAM.

W681307
16.7.9
DF_WR_CNT
Address
0x173E
Access Mode Value At Reset Nominal Value
R/W
00
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
DF_WR_CNT [7:0]
Bit 1
DF_WR_CNT
CPU current write-point. (unit: byte)
Write this byte will force CPU write point set to the DF_WR_CNT value.
16.7.10
DF_RD_CNT
Address
0x173F
Access Mode Value At Reset Nominal Value
R/W
00
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
DF_RD_CNT [7:0]
DF_RD_CNT
CPU current read-point. (unit: byte)
Write this byte will force CPU read point set to the DF_RD_CNT value.
Bit 0
Bit 0
16.8
Example of W25X20/40/80 Serial Flash
1. Write Enable(0x1734 = 06) / Write Disable(0x1734 = 04) / Chip Erase(0x1734 = C7) / Power-down(0x1734 = B9)
0x1730 = 0x81// Set DF_enb, CLK = CPU clock / 2
0x1734 = 0x06// Set CMD Byte1 0x06 / 0x04 / 0xC7 / 0xB9 (code)
0x1731 = 0x00// Force 1 byte TX (CMD)
2. Read Status Register(0x1734 = 05)
0x1730 = 0x87// Set DF_enb, CLK = CPU clock / 8
0x1732 = 0x00// Set CMD Data Field Length = 1 byte
0x1734 = 0x05// Set Byte1 0x05 (code)
0x1731 = 0x18// Force 1 byte TX (CMD), and 1 byte RX
3. Write Status Register(0x1734 = 01)
0x1730 = 0x8A// Set DF_enb, CLK = CPU clock / 11
0x1734 = 0x01// Set CMD Byte1 0x01 (code)
0x1735 = 0x04// Set CMD Byte2 0x04 (S7-S0)
0x1731 = 0x01// Force 2 bytes TX (CMD)
4. Block Erase(0x1734 = D8) / Sector Erase(0x1734 = 20)
0x1730 = 0x8A// Set DF_enb, CLK = CPU clock / 11
0x1734 = 0xD8// Set CMD Byte1 0xD8 / 0x20 (code)
0x1735 = 0x34// Set CMD Byte2 0x34 (A23-A16)
0x1736 = 0x35// Set CMD Byte3 0x35 (A15-A8)
0x1737 = 0x36// Set CMD Byte4 0x36 (A7-A0)
0x1731 = 0x03// Force 4 bytes TX (CMD)
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Publication Release Date: May, 2007
Revision 1.3