Physical Layer; Communication Protocol - STMicroelectronics STM32 Cortex-M3 Manual

2 Electrocardiogram (Ecg) Signals
The Electrocardiogram (Ecg)
• Ecg: electrical manifestation of heart activity recorded
from the body surface
• monitoring of heart rate
The third line is used when a slave want to tell the master something. An interrupt is generated
The Ecg signal can be recorded fairly easily with surface
then.
electrodes placed on the limbs and/or the chest, see pages
below.

4.15.1 Physical layer

I C Definitions
Data can only be transmitted when the bus is not active.
As long as the clock is high, the data line is not allowed to change.
When no data are transmitted, SCL and SDA are high.
Josef Goette

4.15.2 Communication Protocol

1. The data transfer starts with the start bit. The clock is High, data changes from High to Low,
see Figure 4.20
2. The slave address is transmitted.
3. The R/W Bit (see Figure
if data are written to the slave (R/W = 1).
5
A change of the data during a high clock is interpreted as a control command.
42
Figure 4.17: I C Wiring
Figure 4.18: I C Communication Protocol
2
4.21 and 4.22) defines if data are read from the slave (R/W = 0) or
1 Intro
6–16
5
2009
STM32 Cortex-M3 Tutorial
4 Peripherals