ATSGA204A View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'ATSGA204A' PDF : 93 Pages View PDF
ATSHA204A
Single-Wire Interface
CRC-16 0x33
CRC-16 0x43
Command 0x77
Host
11101110
Device 1 1 0 0 1 1 0 0 1 1 0 0 0 0 1 0
Count
Host
Device
Opcode
Param1
Param2
Param2
Host
Device
Data (0 – N)
Transmit 0x88
Count
Data (1 – N)
00010001
XXXXXXXXXXXXXXXX
CRC-16
CRC-16
Idle
Host
11011101
Device X X X X X X X X X X X X X X X X
5.6 Wiring Configuration for Single-Wire Interface
The Single-Wire Interface allows the connection of the ATSHA204A to a Host using only a single SDA pin
to transfer data in both directions. This interface does not use the SCL pin. The ATSHA204A does not
require a bypass capacitor when wired in this configuration if the impedance of the power and ground
signals back to the power supply is low. Microchip recommends a bypass capacitor always be used for
the best reliability.
To prevent forward biasing the internal diode and drawing current across power planes in the system, the
resistor pull-up on the SDA pin should either be connected to the same supply that is connected to the
VCC pin or to a lower voltage rail.
If the signal levels for SDA are different from the VCC voltage, consult the parametric specifications
section of this document to ensure that the signal levels are such that excessive leakage current is
minimized when in sleep modes. This situation might occur if the ATSHA204A device is physically distant
from the bus master device, or the supply voltage for the bus master is different from the supply voltage
for the ATSHA204A.
© 2018 Microchip Technology Inc.
DS40002025A-page 26
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