The TLE92466ED uses a 32-bit SPI protocol with 8-bit CRC (SAE J1850) for robust
communication. This is a full-duplex, synchronous serial interface operating in
SPI Mode 0.
Parameter
Value
Notes
Frame Size
32 bits
Single transaction
CRC
8-bit SAE J1850
Polynomial 0x1D
Mode
0 (CPOL=0, CPHA=0)
Data sampled on rising edge
Frequency
100 kHz - 10 MHz
Typical: 1-2 MHz
Bit Order
MSB first
Most significant bit first
CS Polarity
Active low
Pull low during transfer
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Bit Position: 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 ... 0
┌───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬─────────┐
MOSI (Write): │ CRC (8) │ ADDR (7) │R/W│ DATA (16) │
└───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴─────────┘
┌───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬─────────┐
MISO (Reply): │ CRC (8) │RM │ STATUS(5) │R/W│ DATA (16) │
└───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴─────────┘
Field Breakdown:
┌──────────────┬──────────┬─────────────────────────────────────────────┐
│ Bits [31:24] │ CRC │ 8-bit CRC checksum (SAE J1850) │
│ Bits [23:17] │ ADDRESS │ 7-bit register address (MOSI) │
│ Bits [23:22] │ RPLY_MOD │ Reply mode indicator (MISO) │
│ Bits [21:17] │ STATUS │ 5-bit status field (MISO) │
│ Bit [16] │ R/W │ 1=Write, 0=Read │
│ Bits [15:0] │ DATA │ 16-bit data payload │
└──────────────┴──────────┴─────────────────────────────────────────────┘
```text
### MOSI (Master Out, Slave In) - Write Frame
```text
Write Transaction Format:
31 24 23 17 16 15 0
┌───────────────────┬─────────────┬───┬───────────────────┐
│ CRC (8) │ ADDR (7) │ 1 │ DATA (16) │
└───────────────────┴─────────────┴───┴───────────────────┘
Computed Target Write Value to
checksum register flag write
Example: Write 0x1234 to register 0x0002 (GLOBAL_CONFIG)
Step 1: Build frame without CRC
Bits [23:17] = 0x01 (0x0002 >> 3 = 0x01, upper 7 bits)
Bit [16] = 1 (Write operation)
Bits [15:0] = 0x1234 (Data to write)
Step 2: Calculate CRC on bits [23:0]
Input: 0x00 0x02 0x34 (3 bytes, address + R/W + data)
CRC : 0xXX (computed)
Step 3: Complete frame
[31:24] = CRC, [23:0] = 0x012341234
```text
### MOSI (Master Out, Slave In) - Read Frame
```text
Read Transaction Format:
31 24 23 17 16 15 0
┌───────────────────┬─────────────┬───┬───────────────────┐
│ CRC (8) │ Don't Care │ 0 │ ADDRESS (16) │
└───────────────────┴─────────────┴───┴───────────────────┘
Computed Ignored Read Full register
checksum flag address
Example: Read register 0x0100 (CH0 SETPOINT)
Step 1: Build frame without CRC
Bits [23:17] = Don't care
Bit [16] = 0 (Read operation)
Bits [15:0] = 0x0100 (Register address)
Step 2: Calculate CRC on bits [23:0]
Input: 0x00 0x00 0x01 0x00 (3 bytes)
CRC : 0xXX (computed)
Step 3: Complete frame
[31:24] = CRC, [23:0] = 0x00000100
```text
### MISO (Master In, Slave Out) - Reply Frame Types
#### Type 1: 16-Bit Reply Frame (Standard)
```text
31 24 23 22 21 17 16 15 0
┌───────────────────┬──┬──┬────────────┬───┬───────────────────┐
│ CRC (8) │ 0│ 0│ STATUS (5) │R/W│ DATA (16) │
└───────────────────┴──┴──┴────────────┴───┴───────────────────┘
Computed Reply Status Echo Register
checksum Mode flags R/W contents
Reply Mode [23:22] = 00b: Standard 16-bit data
Status [21:17]: Error/status indication
R/W [16]: Echoes request R/W bit
Data [15:0]: Register value or last write acknowledgment
```text
#### Type 2: 22-Bit Reply Frame (Extended Data)
```text
31 24 23 22 21 0
┌───────────────────┬──┬──┬──────────────────────────────────┐
│ CRC (8) │ 0│ 1│ EXTENDED DATA (22) │
└───────────────────┴──┴──┴──────────────────────────────────┘
Computed Reply Extended feedback data
checksum Mode (e.g., current measurements)
Reply Mode [23:22] = 01b: Extended 22-bit data
Used for: High-resolution feedback registers
```text
#### Type 3: Critical Fault Frame
```text
31 24 23 22 21 0
┌───────────────────┬──┬──┬──────────────────────────────────┐
│ CRC (8) │ 1│ 0│ Don't Care │
└───────────────────┴──┴──┴──────────────────────────────────┘
Computed Reply Undefined
checksum Mode
Reply Mode [23:22] = 10b: Critical fault condition
Indicates: Severe hardware fault, device in safe state
```text
## SPI Status Codes
### Status Field [21:17] Encoding
```text
Status Bits: 5-bit field in MISO reply
┌──────┬─────────────────────────────────────────────────┐
│ Code │ Meaning │
├──────┼─────────────────────────────────────────────────┤
│00000 │ No error - transaction successful │
│00001 │ SPI frame error - invalid frame format │
│00010 │ Parity/CRC error - checksum mismatch │
│00011 │ Write to read-only register - access denied │
│00100 │ Internal bus fault - hardware issue │
│00101 │ Internal bus fault - alternate code │
│00110 │ Internal bus fault - alternate code │
│xxxxx │ Other codes reserved │
└──────┴─────────────────────────────────────────────────┘
Priority: Lower encoding = higher priority
(If multiple errors, lowest code is reported)
```text
## CRC Calculation
### SAE J1850 CRC-8 Algorithm
```text
Polynomial: 0x1D (x^8 + x^4 + x^3 + x^2 + 1)
Init Value: 0xFF
Final XOR: 0xFF
Bit Order: MSB first
Algorithm Pseudocode:
┌────────────────────────────────────────────────────────┐
│ function calculate_crc8(data[], length): │
│ crc = 0xFF // Initialize │
│ for each byte in data: │
│ crc = crc XOR byte // Mix in data byte │
│ for bit = 0 to 7: // Process 8 bits │
│ if crc & 0x80: // Check MSB │
│ crc = (crc << 1) XOR 0x1D │
│ else: │
│ crc = (crc << 1) │
│ return crc XOR 0xFF // Final inversion │
└────────────────────────────────────────────────────────┘
```text
### CRC Calculation Example
```text
Example: Calculate CRC for write to GLOBAL_CONFIG
Frame contents (before CRC):
Address [23:17] = 0x01
R/W [16] = 1
Data [15:0] = 0x4005
Bytes to CRC (bits [23:0] = 3 bytes):
Byte 0: 0x02 (bits [23:16])
Byte 1: 0x40 (bits [15:8])
Byte 2: 0x05 (bits [7:0])
Step-by-step:
crc = 0xFF
Process 0x02:
crc = 0xFF XOR 0x02 = 0xFD
[bit processing yields]
crc = 0xC5
Process 0x40:
crc = 0xC5 XOR 0x40 = 0x85
[bit processing yields]
crc = 0x7A
Process 0x05:
crc = 0x7A XOR 0x05 = 0x7F
[bit processing yields]
crc = 0x23
Final XOR:
crc = 0x23 XOR 0xFF = 0xDC
Result: CRC = 0xDC
Complete frame: 0xDC024005
```text
## Communication Timing
### SPI Timing Diagram
```text
CSN ─────────┐ ┌──────
└─────────────────────────────────────────┘
tCSS tCSH
SCK ─────────┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌──┐ ┌───────
│ │ │ │ │ │ │ │ │ │ │ │ │ │
└──┘ └──┘ └──┘ └──┘ └──┘ └──┘ └──┘
tSCKH tSCKL 32 clock cycles
SI/SO ─────────┤ B31│ B30│ B29│ ... │ B2 │ B1 │ B0 ├──────
└────┴────┴────┴─────┴────┴────┴────┘
tSU tH
Timing Parameters:
┌────────────────────┬──────┬─────────┬──────┬──────┐
│ Parameter │ Min │ Typical │ Max │ Unit │
├────────────────────┼──────┼─────────┼──────┼──────┤
│ tSCK (Clock period)│ 100 │ - │ - │ ns │
│ tCSS (CS setup) │ 50 │ - │ - │ ns │
│ tCSH (CS hold) │ 50 │ - │ - │ ns │
│ tSU (Data setup) │ 20 │ - │ - │ ns │
│ tH (Data hold) │ 20 │ - │ - │ ns │
│ tCSI (CS inactive) │ 100 │ - │ - │ ns │
└────────────────────┴──────┴─────────┴──────┴──────┘
```text
### Transaction Sequence
```text
Complete Read/Write Sequence:
Transaction 1: Write Command
───────────────────────────────────────────────────────────
MCU → IC: [WRITE CMD: 0xXX + CRC + ADDR + DATA]
IC → MCU: [RESPONSE: Previous register state]
Transaction 2: Read Back (optional verify)
───────────────────────────────────────────────────────────
MCU → IC: [READ CMD: 0xXX + CRC + ADDR]
IC → MCU: [RESPONSE: Current register state]
Timing:
CSN ┐ ┌───┐ ┌───
└───┘ └───┘
T1 T2
Notes:
- Response to write contains previous value
- Read returns current value from addressed register
- Minimum 100ns between transactions
```text
## Transaction Examples
### Example 1: Initialize Global Configuration
```text
Objective: Enable CRC, watchdogs, 3.3V VIO
Register: GLOBAL_CONFIG (0x0002)
Value: 0x4005 (CLK_WD_EN | SPI_WD_EN | CRC_EN)
Transaction Breakdown:
┌────────────────────────────────────────────────────────┐
│ Step 1: Build MOSI frame │
│ Address: 0x0002 → [23:17] = 0x00, [16] = 1 (write) │
│ Data: 0x4005 │
│ Bytes for CRC: [0x02, 0x40, 0x05] │
│ CRC: 0xDC (calculated) │
│ Complete: 0xDC024005 │
│ │
│ Step 2: SPI Transfer │
│ MOSI: 0xDC024005 │
│ MISO: 0xXXXXXXXX (previous register value + status) │
│ │
│ Step 3: Verify (optional) │
│ Read back GLOBAL_CONFIG to confirm │
└────────────────────────────────────────────────────────┘
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Objective: Read CH0 current setpoint
Register: CH0_SETPOINT (0x0100)
Transaction Breakdown:
┌────────────────────────────────────────────────────────┐
│ Step 1: Build MOSI frame │
│ Address: 0x0100 → [15:0] = 0x0100, [16] = 0 (read) │
│ Bytes for CRC: [0x00, 0x01, 0x00] │
│ CRC: 0xXX (calculated) │
│ Complete: 0xXX000100 │
│ │
│ Step 2: SPI Transfer │
│ MOSI: 0xXX000100 │
│ MISO: 0xYY000567 (register value = 0x0567) │
│ └─┬─┘ │
│ CRC │
│ │
│ Step 3: Verify CRC & Extract Data │
│ Status [21:17]: Check for errors │
│ Data [15:0]: 0x0567 = current setpoint │
└────────────────────────────────────────────────────────┘
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Scenario: Write to read-only register
Transaction:
MOSI: Write to ICVID (0x0200, read-only)
MISO: Status = 0b00011 (Write to RO register)
Response Handling:
┌────────────────────────────────────────────────────────┐
│ Parse MISO frame: │
│ [31:24]: CRC → Verify │
│ [23:22]: Reply Mode = 00 (normal) │
│ [21:17]: Status = 0b00011 → ERROR! │
│ [16]: R/W echo │
│ [15:0]: Undefined (ignore) │
│ │
│ Error Response: │
│ - Retry not recommended │
│ - Check register address │
│ - Verify register is writable │
└────────────────────────────────────────────────────────┘
CRC Verification : Always verify outgoing CRC before transmission, verify
incoming CRC after reception, and reject frames with CRC mismatch.
Status Checking : After every transaction, parse the status field
[21:17], handle errors appropriately, and log unexpected status codes.
Timing Compliance : Ensure the minimum CS inactive time is 100 ns,
maintain proper setup and hold times, and keep the clock frequency within
limits.
Error Recovery : On error, check the CRC first, verify the register
address, retry with exponential backoff (maximum three attempts), and reset
communication if the issue persists.
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Recommended SPI Frequency:
┌─────────────────────┬──────────────────────────────────┐
│ Application │ Frequency │
├─────────────────────┼──────────────────────────────────┤
│ Debug/Development │ 100-500 kHz (easier to debug) │
│ Normal Operation │ 1-2 MHz (good balance) │
│ High Performance │ 5-10 MHz (maximum throughput) │
└─────────────────────┴──────────────────────────────────┘
Transaction Rate:
- 32 bits @ 1 MHz = 32 µs per transaction
- +100ns CS gap = ~33 µs total
- Max rate: ~30,000 transactions/second