L99MH98 datasheet(52/147 Pages) STMICROELECTRONICS

52 / 147 page

6.4.3

Clear on read scenario

When a clear on read communication must be performed the following steps must be considered:

•

Frame n

–

SDI:

◦

Bit 23 = 0 (read command on the OpCode)

◦

Bit 22 = Not used

◦

Bits 21 to 16 = Address of the register to read

◦

Bits 15 to 1 = Set to 0 the bits “not to clear”, set to 1 the bits “to clear”

◦

Bit 0 = Parity bit

–

SDO:

◦

Bit 23 = 0 (no SPI error or RESET in the previous access)

◦

Bit 22 = GSBN bit (1 = No fault)

◦

Bits 21 to 16 = Address of the register selected in the previous frame (n-1)

◦

Bits 15 to 1 = Data value of the register selected in the previous frame (n-1)

◦

Bit 0 = Parity bit

•

Frame n+1

–

SDI:

◦

Bit 23 = 0 or 1 (read or write command on the OpCode)

◦

Bit 22 = Not used

◦

Bits 21 to 16 = Address of the register to read or write

◦

Bits 15 to 1 = Data to write into the chosen register

◦

Bit 0 = Parity bit

–

SDO:

◦

Bit 23 = 0 (no SPI error or RESET in the previous access)

◦

Bit 22 = GSBN bit (1 = No fault)

◦

Bits 21 to 16 = Address of the register selected in the previous frame (n)

◦

Bits 15 to 1 = Data value of the register selected in the previous frame (n) with the bits cleared

◦

Bit 0 = Parity bit

Figure 35. Clear on Read scenario

Frame n

0 = Read

Address of the register

to read reg1

Clear on read register bit15, bit14 and bit1 are set to ‘1’

Data field: bit15 is set to ‘0’  not to clear,

while bit14 and bit1 are set to ‘1’  to clear

Frame n+1

After frame n cs rising edge, the clear on read is executed to bit 14 and bit1 as commanded



now the register value is with only bit15 set to ‘1’

Data value of reg1 (selected by SDI during previous

frame (n)) saved at frame n+1 cs falling

L99MH98

Serial peripheral interface (SPI)

DS14611 - Rev 3

page 52/147

L99MH98 датащи(PDF) 52 Page - STMicroelectronics

L99MH98 датащи(HTML) 52 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL