PRELIMINARY ISD1700 SERIES
Publication Release Date: Nov 6, 2008
- 32 -
Revision 1.31
10.2.2 MOSI Data Format
MOSI
is the
M
aster
O
ut
S
lave
I
n data line of the SPI interface. Data is clocked into the device
on the rising edge of the SCLK signal, with the least significant bit (LSB) first. Depending
upon the command type, the format may be two bytes or as long as seven bytes. The
generalized sequence of MOSI data is shown in the table below. The first byte sent to the
device is always the command opcode byte, which determines the operation to be
performed. Bit 4 (C4) of the command byte determines whether the LED feature is activated
for related operations. When C4=1, the LED is On. Subsequent bytes are data associated
with the type of command, which may include start and end addresses for operation or other
data bits.
Table 10.1 MOSI Data Sequence
MSB 1
st
Byte: Command Byte LSB
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
C7 C6 C5 C4 C3 C2 C1 C0
MSB 2
nd
Byte: Data Byte1 LSB
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
X/D7 X/D6 X/D5 X/D4 X/D3 X/D2 X/D1 X/D0
MSB 3
rd
Byte: Data Byte2 / Start Address Byte1 LSB
Bit 23
Bit 22
Bit 21
Bit 20
Bit 19
Bit 18
Bit 17
Bit 16
X/S7 X/S6 X/S5 X/S4
D11/S3 D10/S2
D9/S1
D8/S0
MSB 4
th
Byte: Data Byte3 / Start Address Byte2 LSB
Bit 31
Bit 30
Bit 29
Bit 28
Bit 27
Bit 26
Bit 25
Bit 24
X X X X X
S10
S9
S8
MSB 5
th
Byte: End Address Byte1 LSB
Bit 39
Bit 38
Bit 37
Bit 36
Bit 35
Bit 34
Bit 33
Bit 32
E7 E6 E5 E4 E3 E2 E1 E0
MSB 6
th
Byte: End Address Byte2 LSB
Bit 47
Bit 46
Bit 45
Bit 44
Bit 43
Bit 42
Bit 41
Bit 40
X X X X X
E10
E9
E8
MSB 7
th
Byte: End Address Byte3 LSB
Bit 55
Bit 54
Bit 53
Bit 52
Bit 51
Bit 50
Bit 49
Bit 48
X X X X X X X X
Note: X = Don’t care (Recommend 0)
Majority of commands are two-byte commands. The DEV_ID, RD_STATUS and WR_APC
command are three-byte, in which the 2
nd
and 3
rd
bytes are data for WR_APC. The, RD_APC
and Read pointer commands are four-byte. However, SET commands are seven-byte with
Start address <S10:S0> and End address <E10:E0> and the rest address bits are reserved
for future use (recommend 0). Address count starts at address 0x000, which is the start
location of the first Sound Effect. Address locations 0x000-0x00F inclusively are reserved
equally for 4 sound effects. Address 0x010 is the first address of non-reserved storage. For
minimum storage resolution, please refer to Section 6.2.
