90E36 Datasheet, PDF (27/79 Pages) Integrated Device Technology – Poly-Phase High-Performance Wide-Span Energy Metering IC

90E36
POLY-PHASE HIGH-PERFORMANCE WIDE-SPAN ENERGY METERING IC
4
SPI / DMA INTERFACE
4.1 INTERFACE DESCRIPTION
The interface can work in two modes: Slave (SPI) mode and Master
mode, which is also named DMA (Direct Memory Access) mode. The
interface mode is determined by the DMA_CTRL pin as below:
Mode
Slave (SPI) Mode
Master (DMA) Mode
DMA_CTRL
0
1
Description
The interface works as normal four-
wire SPI interface.
The interface operates as a master
and dumps data to the other
devices.
Five pins are associated with the interface as below:
• SDI – Data pin, bi-directional.
• SDO – Data pin, bi-directional.
• SCLK – Bi-directional pin. It is a clock output pin in master mode
and clock input pin in slave mode.
• CS – Bi-directional chip select pin . It is an output pin in master
mode and input pin in slave mode.
• DMA_CTRL – Uni-directional input pin. The external device pull
this pin high to control the interface work in master mode for data
dumping in DMA mode.
SPI Interface logic
(As slave)
SDI
SDO
SCLK
CS
DMA_CTRL
MOSI
MISO
SCK
CS
DMA_CTRL=0
Host controller in
master mode
MOSI
MISO
SCK
GPIO1
GPIO2
Figure-12 Slave Mode
SPI Interface logic
(As master)
SDI
MOSI
DSP slave mode
MOSI
SDO
MISO
MISO
SCLK
CS
SCK
CS
SCK
SPISS
DMA_CTRL
DMA_CTRL=1
GPIO
Figure-13 Master Mode (PIN_DIR_SEL=0)
SPI / DMA Interface
27
December 9, 2011