BR93H76-2C_16 Datasheet, PDF (13/33 Pages) Rohm – Operation Microwire BUS EEPROM

BR93H76-2C
Datasheet
Description of Operation
Communications of the Microwire Bus are carried out by SK (serial clock), DI (serial data input), DO (serial data output), and
CS (chip select) for device selection.
In connecting one EEPROM to a microcontroller, connect it as shown in Figure.29-(a) or Figure.29-(b). And, when using the
input and output common I/O port of the microcontroller, connect DI and DO via a resistor as shown in Figure.29-(b) (Refer to
pages 19/29), wherein connection by 3 lines is possible.
In case of using multiple EEPROM devices, refer to Figure. 29-(c).
Micro-
controller
CS
BR93H76
CS
Micro-
controller
CS
BR93H76
CS
SK
SK
SK
SK
DO
DI
DO
DI
Micro-
controller
CS3
CS1
CS0
SK
DO
DI
DI
DO
DO
Device 1
Device 2
Device 3
Figure 29-(a). Connection by 4 lines Figure 29-(b). Connection by 3 lines Figure 29-(c). Connection example of multiple devices
Figure 29. Connection Methods with Microcontroller
Communications of the Microwire Bus are started by the first “1” input after the rise of CS. This input is called the “Start Bit”.
After input of the start bit, the “Ope Code”, Address, and Data are then inputted consecutively. Address and Data are all
inputted with MSB first.
All “0” signal inputs after the rise of CS up to the start bit is ignored. Therefore, if there is a limitation in the bit width of PIC of
the microcontroller, it is possible to input “0” before the start bit to control the bit width.
Command Mode
Command
Read (READ)
Start
bit
(1)
1
Ope
code
10
Address
BR93H76-2C
＊,A8,A7,A6,A5,A4,A3,A2,A1,A0
Data
D15 to D0(READ DATA)
Write enable (WEN)
Write (WRITE)
Write all (WRAL)
1
(2)
1
(2,3)
1
00
1 1 ＊＊＊＊＊＊＊＊
－
01
＊,A8,A7,A6,A5,A4,A3,A2,A1,A0 D15 to D0(WRITE DATA)
00
0 1 ＊ ＊ ＊ ＊ ＊ ＊,B1,B0 D15 to D0(WRITE DATA)
Write disable (WDS)
1
00
0 0 ＊＊＊＊＊＊＊＊
－
・ Input the address and the data in MSB-first order.
・ As for *, input either VIH or VIL.
*Start bit
Acceptance of all the commands of this IC starts at recognition of the start bit.
The “Start Bit” means the first “1” input after the rise of CS.
(1) For READ, after setting the command, the data output of the selected address starts. Then, in a sequential order of addresses,
the data of the next address will be outputted , and will continuously output data of succeeding addresses with the use of a continuous SK clock input.
(Auto-Increment Function)
(2) When the WRITE and the WRITE-All commands are executed, the previous data written in the selected memory cell are automatically deleted first, then the
input data is written next.
(3) For the write all command, data written in memory cell of the areas designated by B1, and B0 are automatically deleted, and input data is written in bulk.
Write All Area
B1 B0
00
Write area
000h to 07Fh
ï½¥The write all command is written in bulk in 2Kbit unit.
The write area can be selected up to 2bit. Confirm on
the left side the settings and write areas of B1, and B0.
01
080h to 0FFh
10
100h to 17Fh
11
180h to 1FFh
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16.Feb.2016 Rev.003