GD32W51x User Manual
1014
Figure 30-7. HPDF module external input data processing flow
External
sigma-delta
modulation
Serial
interface
transceiver
Sinc filter
Integrator
Data unit
The output data rate depends on the serial data stream rate, filter and integrator settings. The
maximum output data rate is shown in the table below.
Table 30-8. Maximum output rate
Input source Conversion m ode
Filter type
Maxim um output data rate
(sam ples/second)
Serial input
Non-fast mode
(FAST=0)
Sinc
X
f
CKIN
SFOR×
(
IOR-1+SFO
)
+(SFO+1)
Non-fast mode
(FAST=0)
FastSinc
f
CKIN
SFOR×
(
IOR-1+4
)
+(2+1)
Fast mode (FAST=1)
FastSinc and
Sinc
X
f
CKIN
SFOR×IOR
Parallel input
Non-fast mode
(FAST=0)
Sinc
X
f
DATA
SFOR×
(
IOR-1+SFO
)
+(SFO+1)
Non-fast mode
(FAST=0)
FastSinc
f
DATA
SFOR×
(
IOR-1+4
)
+(2+1)
Fast mode (FAST=1)
FastSinc and
Sinc
X
f
DATA
SFOR×IOR
Note:
f
DATA
is the parallel data rate of the CPU/DMA input. When the filter is bypassed, f
DATA
≤
f
HPDFCLK
must be satisfied.
Signed data format
Signed data in HPDF module: parallel data register, regular and inserted group data register,
threshold monitor vlaue, extreme monitor value, and offset calibration are all signed formats.
The most significant bit of the output data indicates the sign of the value, and the data is in
two's complement format.
Since all operations in digital processing are performed on 32-bit signed registers, the
following conditions must be met in order for the result not to overflow:
1.
When using Sinc
X
filter (x=1..5): (SFOR
SFO
)
×
IOR ≤ 2
31
.
2.
When using FastSinc filter: 2
×
(SFOR
2
)
×
IOR ≤ 2
31
.
Data right bit shift
Since the final data width is 24 bits and the data from the processing path can be up to 32
bits, the right shift of the final data is performed in this module. For each selected input
channel, the number of bits shifted to the right can be configured in the DTRS[4:0] bit field in