RT9428

9

DS9428-01

October 2014

www.richtek.com

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Copyright

2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Table 2. Control Register Commands

Value

Command

Description

4000h

Quick

Sensing

Restart sensing and

SOC calculation

VBAT

The VBAT register is a read only register that reports the

measured voltage at VBAT pin. The VBAT is reported in

units of 1.25mV. The first report is made after chip POR

with 250ms delay and then updates 1s periodically. Figure

1 shows the VBAT register format.

SOC

The SOC register is a read only register that returns the

relative state of charge of the cell as calculated by the

voltaic gauge algorithm. The result is displayed as a

percentage of the cell's full capacity. The high byte is

reported in units of %. The low byte is reported in units of

1/256%. Figure 2 shows the SOC register format.

Figure 1. VBAT Register

Figure 2. SOC Register

MSB-Address 04h

MSB

2

7

LSB MSB

LSB

LSB-Address 05h

2

5

2

6

2

4

2

3

2

2

2

1

2

0

2

-1

2

-2

2

-3

2

-4

Unit : 1%

2

-5

2

-6

2

-7

2

-8

Control

The Control register allows the host processor to send

special commands to the IC (Table2). Valid Control register

write values are listed as follows. All other Control register

values are reserved.

Address

(Hex)

Register

Description

Read/

Write

Default

(Hex)

02h-03h

VBAT

It reports voltage measured from the input of VBAT pin.

R

--

04h-05h

SOC

It reports the SOC result calculated by voltaic-gauge algorithm.

R

--

06h-07h

Control

It's the command interface for special function such as Quick

Sensing.

W

--

08h-09h

Device ID

It reports the device ID.

R

--

0Ah

Status

It reports alert status.

R/W

01h

0Bh

dSOC

It reports approximately incremental SOC in unit of 1% per

hour.

R

--

0Ch-0Dh

Config

The Config register includes the parameter of compensation,

setting of sleep mode and SOCLow threshold. It also indicates

the alert status.

R/W

321Ch

0Eh-0Fh

OCV

It reports Open Circuit Voltage corresponding to present SOC in

unit of 1.25mV.

R

--

FEh-FFh

MFA

Manufacturer Access. Sends special commands to the IC for

the manufacturing.

W

--

MSB-Address 02h

MSB

2

11

LSB MSB

LSB

LSB-Address 03h

0

0

0

0

2

9

2

10

2

8

2

7

2

6

2

5

2

4

2

3

2

2

2

1

2

0

0 : Bits Always Read Logic 0

Unit : 1.25mV

Initialization

The RT9428 can be reset by writing an initialization

command to MFA resister. The behavior of initialization is

the same as power on reset.

VBAT, SOC, Control, Device ID, Config and MFA.

The register writing is valid when all of 16 bits data are

transferred; otherwise, the write data will be ignored. The

valid register addresses are defined in Table 1. Other

remaining addresses are reserved.