M93C86 datasheet(9/37 Pages) STMICROELECTRONICS

tên linh kiện	M93C86

Giải thích chi tiết về linh kiện	16 Kbit, 8 Kbit, 4 Kbit, 2 Kbit and 1 Kbit (8-bit or 16-bit wide)

PDF	37 Pages

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nhà sản xuất	STMICROELECTRONICS [STMicroelectronics]

Trang chủ	http://www.st.com

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M93C86, M93C76, M93C66, M93C56, M93C46

Connecting to the serial bus

Doc ID 4997 Rev 10

9/37

Connecting to the serial bus

Figure 3 shows an example of three memory devices connected to an MCU, on a serial bus.

Only one device is selected at a time, so only one device drives the Serial Data output (Q)

line at a time, the other devices are high impedance.

The pull-down resistor R (represented in Figure 3) ensures that no device is selected if the

bus master leaves the S line in the high impedance state.

In applications where the bus master may be in a state where all inputs/outputs are high

impedance at the same time (for example, if the bus master is reset during the transmission

of an instruction), the clock line (C) must be connected to an external pull-down resistor so

that, if all inputs/outputs become high impedance, the C line is pulled low (while the S line is

pulled low): this ensures that C does not become high at the same time as S goes low, and

so, that the tSLCH requirement is met. The typical value of R is 100 kΩ.

Figure 3.

Bus master and memory devices on the serial bus

AI14377b

Bus master

M93xxx

memory device

SDO

SDI

SCK

CQD

M93xxx

memory device

CQD

M93xxx

memory device

CQD

CS3 CS2 CS1

ORG

VCC

VSS

M93C86 bảng dữ liệu(PDF) 9 Page - STMicroelectronics