AMG-XB404 Datasheet, PDF (40/73 Pages) alpha microelectronics gmbh – Fully Integrated Single Motor Controller for Electrical Motors

AMG-XB404
Fully Integrated Single Motor Controller for Electrical Motors
resulting
SDA
MSB
SDA from
IO expander
SDA from
EEPROM
SCL from
IO expander
address[6:0]
LSB R/W ACK
Figure 21: Serial two-wire communication address
cycle
As shown in figure 22 a data cycle contains eight data bits and one acknowledge bit. Data is sent
MSB first. The receiving side acknowledges the received data by pulling SDA low.
resulting
SDA
MSB
SDA from
transmitter
SDA from
receiver
SCL from
IO expander
8-Bit data
LSB ACK
Figure 22: Serial two-wire communication data
cycle
When data is sent from IO expander to EEPROM the EEPROM may set STOPREG to send a non-
acknowledge after receiving the next byte from the IO expander, thus indicating that it will receive
no more data. The EEPROM will enter a passive state after STOPREG has been set until a start
condition is received. If data requested by the IO expander is not ready to be sent by the EEPROM
the EEPROM will pull the serial clock to LOW until the data is ready. This is the only case in which
the EEPROM influences the serial clock.
All serial communication is initiated by a device address word (see figure 23) indicating the
EEPROM address and the read/write access mode, writes have the LSB set to 0, reads have the
LSB set to 1. For the AMG-XB404 the EEPROM address is always zero. The device address word
will be acknowledged if the IC is ready.
MSB
LSB
1 0 1 0 A2 A1 A0 R/W
Figure 23: Device address word
EEPROM Writes
The 256 kBit EEPROM is capable of up to 64-byte page writes. A page write operation requires the
device address word followed by a 16 bits wide start byte address, up to 64 bytes of data, and a
stop condition to initiate a self-timed EEPROM write. This is shown in figure 24. It can be seen that
all data and address bytes need to be acknowledged by setting the data line low. Writes start at the
given byte address, the address is incremented automatically.
AMG-XB404
Revision: A
2. Nov. 2012 © All rights reserved
Page 40 of 73