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SPI Command
The audio processor uses the SPI interface as the communication interface with two
methods of communicating through the internal (SPICR[7]=1) SPI circuit or the external
(SPICR[7]=0) pin-shared I/Os. The internal communication can execute the circuit control
through the control bit as the following shows:
SPI Control Register (SPICR)
Bit #
7
6
SPICR
IEMC
-
POR
1
-
SPICK
SPICR[7]=1
SPICR[3]
SPICR[7]=0
PC6
One complete data transmission is 20 bits long, starting transmission from the MSB to the
th
20
bit LSB. This includes a 4-bit group command and 16 bits of data. The group
contains both I/O and CLI. The I/O command is used in some application areas, such as
for circuit control, sharing data etc, marked as I/O CMD-NNh in this document. The CLI
(control layer interface) command can access the audio processor related parameters,
such as the threshold parameters, modulation, advanced application control and so on.
Its usage is different from the I/O group and requires three commands to completely write
a command. Reading data requires two commands. These are marked as CLI
CMD–NNNNh in this document. See the following for details:
SPISS
SPISS
SPICK
SPICK
C3
C3
C2
C2
C1
C1
MOSI
MOSI
C3
C3
C2
C2
C1
C1
MISO
MISO
SPIRQ
SPIRQ
HT98R068 SPI Communication Format
HT98R068 Two-way Radio MCU
5
4
ERAM
SPISS
0
1
MOSI
MISO
SPICR[2]
SPICR[1]
PC4
PA5
SPI Control Signal Table
C0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
C0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
C0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
C0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
7
3
2
1
SPICK
MOSI
MISO
0
0
x
SPISS
SPICR[4]
PC7
0
SPIRQ
x
SPIRQ
SPICR[0]
PC5
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