AK5556 Datasheet, PDF (57/69 Pages) Asahi Kasei Microsystems – 6-Channel Differential 32-bit ADC

[AK5556]
■ Operation Mode Control
Operation modes of the AK5556 are set by pins or registers. In parallel control mode, the operation mode
is set by pin and register settings are invalid. Therefor the functions that needs register settings are not
available in parallel control mode. For register accessing, 3-wire serial and I²C bus communications are
available. This control mode of the AK5556 is selected by the I2C pin and the PSN pin. In serial control
mode, register settings are prioritized so that all pin settings except the MSN pin setting are ignored.
I2C pin
L
L
H
H
PSN pin
Control mode
L
3-wire Serial
H
3-wire Serial
L
I²C Bus
H
Parallel
Table 22. Control Mode
■ Register Control Interface
(1) 3-wire Serial Control Mode (I2C pin = “L”)
The internal registers may be written through the 3-wire µP interface pins (CSN, CCLK and CDTI). The
data on this interface consists of a 2-bit Chip address, Read/Write (1bit, Fixed to “1”, Write only), Register
address (MSB first, 5bits) and Control data (MSB first, 8bits). Address and data are clocked in on the
rising edge of CCLK and data is clocked out on the falling edge. For write operations, data is latched after
a low-to-high transition of CSN. The clock speed of CCLK is 5MHz (max).
The internal registers are initialized by setting the PDN pin = “L”. In serial control mode, an internal timing
circuit is reset by setting RSTN bit = “0” but register values are not initialized.
CSN
CCLK
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
CDTI
C1 C0 R/W A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
C1-C0: Chip Address (C1=CAD1, C0=CAD0)
R/W: READ/WRITE (Fixed to “1”, Write only)
A4-A0: Register Address
D7-D0: Control Data
Figure 62. Control I/F Timing
* The AK5556 does not support read commands in 3-wire serial control mode.
* When the AK5556 is in power down mode (PDN pin = “L”), a writing into the control registers is
prohibited.
* The control data cannot be written when the CCLK rising edge is 15 times or less, or 17 times or more
during CSN is “L”.
015099857-E-00
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2016/03