HAL-APB-V1.5 Datasheet, PDF (35/59 Pages) Micronas – Application Board HAL-APB V1.x

APPLICATION NOTE
HAL1820, HAL24xy, HAL28xy, HAL36xy, HAL38xy
Application Board HAL-APB V1.x
9.5. Available sensor commands
The sensor supports 3 commands which provide read and write access to the whole memory
(NVRAM;ROM, RAM, register).
The used write data frame and read data frame contains of 5 address bits only. A set base
address command which defines a base address, expands the accessible address range to 8 bit.
In case of a unknown command, the sensor does neither transmit an acknowledge nor a body.
Table 9–15: Available sensor commands
Command
Read
COM b[2:0] frame
type
1
read
Set base address 3
Write
6
write
write
ADR b[4:0]
offset address
(0 to 31)
don’t care
offset address
(0 to 31)
DAT b[15:0] (RD/WD)
data read from address = ADR
base address 0,1,2,3
data which is written to address = ADR
9.5.1. Set base address
The set base address telegram functions as preparation for the write telegram and the read tele-
gram. It uses the write data frame. Bit [15:2] are don’t care bit 0 and bit1 are concatenated to the
address.The sensor transmits an acknowledge if a communication error has not been detected.
9.5.2. Read
The read telegram uses the read data frame. The sensor transmits the data of the effective
address after the header has been successful received and the effective address is permitted.
Otherwise, the sensor does not respond.
The effective address is calculated by the base address plus offset address. The offset address
is defined by the address bits of the header (A b[4:0]).
9.5.3. Write
The write telegram uses the write data frame. The sensor saves the received address to the cal-
culated effective address and transmits an acknowledge after the header and body has been
successful received and the effective address is permitted. Otherwise, the command is discarded
and the sensor transmits no acknowledge.
A write telegram is also discarded while EEPROM programming. During the NVPROM program-
ming sequence, a write command is discarded.
9.5.4. CRC
The data bits are always followed by 4 CRC bits. For all commands but read the CRC result is
calculated of all protocol bits, including command, address, parity and data bits.
For read command, the CRC result is calculated of data bits only (16).
The polynomial for the CRC calculation is always X⁴+X+1.
In case of correct command detection (parity, CRC and command address if applicable), an ACK
is sent as an answer.
Micronas
Oct. 8, 2012; APN000055_003EN
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