HT98R068 Two-way Radio MCU
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
5
4
3
2
1
0
SPICR IEMC
-
ERAM
SPISS
SPICK
MOSI MISO SPIRQ
POR 1 - 0 1 0 0 x x
SPICK
MOSI
MISO
SPISS
SPIRQ
SPICR[7]=1 SPICR[3] SPICR[2] SPICR[1] SPICR[4] SPICR[0]
SPICR[7]=0
PC6 PC4 PA5 PC7 PC5
SPI Control Signal Table
One complete data transmission is 20 bits long, starting transmission from the MSB to the
20
th
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
SPICK
MOSI
MISO
C2
C1
C0 D15 D14 D13 D12 D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
C2
C1
C0 D15 D14 D13 D12 D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
C3
C3
SPIRQ
SPISS
SPICK
MOSI
MISO
C2
C1
C0 D15 D14 D13 D12 D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
C2
C1
C0 D15 D14 D13 D12 D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
C3
C3
SPIRQ
HT98R068 SPI Communication Format
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