Specifications

Peripheral Interfaces
 DSP56800 Hardware Interface Techniques 21
Figure 19. Serial 10-bit, 4-Channel D/A Converter
4.4 PWM Interface
The sections below describe example interfaces to the PWM module(s) available on DSP56800
devices.
The DSP56F807 has two independent groups of dedicated PWM units. Each unit contains six PWM,
three Phase Current sense and four Fault input lines. PWM group A’s PWM lines are connected to a
UNI-3 interface connector and to a set of six PWM LEDs via inverting buffers. “UNI-3” refers to a
Freescale-defined parallel interface. Typically, any parallel cable, such as a HDD cable, will satisfy the
requirements of the DSP56800 device. The inverting buffers are used to isolate and drive the DSP’s
PWM group A’s outputs to the PWM LEDs. The PWM LEDs indicate the status of PWM group A
signals, as shown in Figure 20.
Figure 20. PWM Group A Interface and LEDs
DSP56F807
MAX5251
D/A CONNECTOR
MOSI
MISO
SCLK
PB4
RSTO
DIN
DOUT
SCLK
CS
CL
OUT A
OUT B
OUT C
OUT D
Vref
1
3
5
7
2
4
6
8
D/A 0
D/A 1
D/A 2
D/A 3
J1
+3.3VA
10K
R1
DSP56F807
LED
BUFFER
UNI-3
PWMA0
PWMA1
PWMA2
PWMA3
PWMA4
PWMA5
PWMA0
PWMA1
PWMA2
PWMA3
PWMA4
PWMA5
YELLOW LED
GREEN LED
GREEN LED
GREEN LED
YELLOW LED
YELLOW LED
+3.3V
PHASE A TOP
PHASE A BOTTOM
PHASE B TOP
PHASE B BOTTOM
PHASE C TOP
PHASE C BOTTOM
LED4
LED5
LED6
LED7
LED8
LED9
Freescale Semiconductor, I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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