DTMFDECODER-RD Silicon Laboratories Inc, DTMFDECODER-RD Datasheet - Page 158

• Manufacturer Part Number: DTMFDECODER-RD
• Description: KIT REF DESIGN DTMF DECODER
• Manufacturer: Silicon Laboratories Inc

Specifications of DTMFDECODER-RD

• Mfg Application Notes: DTMF Decoder Ref Design AppNote
• Main Purpose: Telecom, DTMF Decoder
• Embedded: No
• Utilized Ic / Part: C8051F300
• Primary Attributes: 8kHz Sampling Rate ADC
• Secondary Attributes: 16 Goertzel Filters
• Processor To Be Evaluated: C8051F300
• Interface Type: RS-232
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 336-1283

C8051F300/1/2/3/4/5
16.2.1. Edge-triggered Capture Mode
In this mode, a valid transition on the CEXn pin causes the PCA to capture the value of the PCA counter/
timer and copy it into the corresponding module's 16-bit capture/compare register (PCA0CPLn and
PCA0CPHn). The CAPPn and CAPNn bits in the PCA0CPMn register are used to select the type of transi-
tion that triggers the capture: low-to-high transition (positive edge), high-to-low transition (negative edge),
or either transition (positive or negative edge). When a capture occurs, the Capture/Compare Flag (CCFn)
in PCA0CN is set to logic 1 and an interrupt request is generated if CCF interrupts are enabled. The CCFn
bit is not automatically cleared by hardware when the CPU vectors to the interrupt service routine, and
must be cleared by software. If both CAPPn and CAPNn bits are set to logic 1, then the state of the Port
pin associated with CEXn can be read directly to determine whether a rising-edge or falling-edge caused
the capture.
Note: The CEXn input signal must remain high or low for at least 2 system clock cycles to be recognized by the
158
Port I/O
hardware.
Crossbar
Figure 16.4. PCA Capture Mode Diagram
CEXn
W
P
M
1
6
n
x
PCA0CPMn
O
M
E
C
n
0
Rev. 2.9
C
A
P
P
n
C
A
P
N
n
0
1
M
A
T
n
0 0 0 x
T
O
G
n
W
M
P
n
E
C
C
F
n
0
1
C
F
C
R
PCA0CN
PCA
Timebase
C
C
F
2
C
C
F
1
C
C
F
0
PCA Interrupt
Capture
PCA0CPLn
PCA0L
PCA0CPHn
PCA0H