Rainbow Electronics MAX16068 - Manual (Page 25)

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MAX16068
6-Channel, Flash-Configurable System Manager
with Nonvolatile Fault Registers
Acknowledge
The acknowledge bit (ACK) is the 9th bit attached to
any 8-bit data word. The receiving device always gener-
ates an ACK. The MAX16068 generates an ACK when
receiving an address or data by pulling SDA low during
the 9th clock period (Figure 8). When transmitting data,
such as when the master device reads data back from
the MAX16068, the device waits for the master device to
generate an ACK. Monitoring ACK allows for detection
of unsuccessful data transfers. An unsuccessful data
transfer occurs if the receiving device is busy or if a sys-
tem fault has occurred. In the event of an unsuccessful
data transfer, the bus master can reattempt communica-
tion at a later time. The MAX16068 generates a NACK
after the command byte received during a software
reboot, while writing to the flash, or when receiving an
illegal memory address.
Slave Address
Use the slave address input, A0, to allow multiple identi-
cal devices to share the same serial bus. Connect A0 to
GND, DBP (or an external supply voltage greater than
2V), SCL, or SDA to set the device address on the bus.
See Table 18 for a listing of all possible 7-bit addresses.
The slave address can also be set to a custom value by
loading the address into register r8Bh[6:0]. See Table
19. If r8Bh[6:0] is loaded with 00h, the address is set by
input A0. Do not set the address to 09h or 7Fh to avoid
address conflicts. The slave address setting takes effect
immediately after writing to the register.
Figure 8. Acknowledge
Table 18. Setting the SMBus Slave Address
R = Read/write select bit.
SCL
1
S
2 8 9
SDA BY
TRANSMITTER
SDA BY
RECEIVER
CLOCK PULSE FOR ACKNOWLEDGE
NACK
ACK
SLAVE ADDRESSES
A0 SLAVE ADDRESS
0 1010 100R
1 1010 101R
SCL 1010 110R
SDA 1010 111R