Product Specs

Table Of Contents
33 TWIM I
2
C compatible two-wire interface
master with EasyDMA
Page
305
33 TWIM I
2
C compatible two-wire interface master
with EasyDMA
TWI master with EasyDMA (TWIM) is a two-wire half-duplex master which can communicate with multiple
slave devices connected to the same bus
Listed here are the main features for TWIM:
I
2
C compatible
100 kbps, 250 kbps, or 400 kbps
Support for clock stretching
EasyDMA
The two-wire interface can communicate with a bi-directional wired-AND bus with two lines (SCL, SDA).
The protocol makes it possible to interconnect up to 127 individually addressable devices. TWIM is not
compatible with CBUS.
The GPIOs used for each two-wire interface line can be chosen from any GPIO on the device and are
independently configurable. This enables great flexibility in device pinout and efficient use of board space
and signal routing.
TXD buffer
SDA
SCL
RXD buffer
Figure 77: TWI master with EasyDMA
A typical TWI setup consists of one master and one or more slaves. For an example, see Figure 78: A typical
TWI setup comprising one master and three slaves on page 306. This TWIM is only able to operate as a
single master on the TWI bus. Multi-master bus configuration is not supported.
TWIM
GPIO
RAM
RXD.PTR
TXD.PTR
Pin
Pin
PSEL.SCK
EasyDMA
RXD-1
EasyDMA
TXD+1
buffer[0]
buffer[1]
buffer[TXD.MAXCNT-1]
PSEL.SDA
STARTRX
STARTTX
RXSTARTED
TXSTARTED
LASTTX
LASTRX
SUSPENDED
SUSPEND
RESUME
ERROR
STOPPED
STOP
buffer[0]
buffer[1]
buffer[RXD.MAXCNT-1]