NAME
mcp3kadc —
Microchip 3x0x SAR analog to
digital converter
SYNOPSIS
mcp3kadc* at spi? slave ? flags N
DESCRIPTION
The
mcp3kadc driver reports the current voltage on the chip's
ADC channels through the
envsys(4) API. The driver
calculates these values according to the currently selected reference voltage
(
Vref
). It can be changed through the
sysctl(8) node
hw.mcp3kadc0.vref
.
The following table shows the supported chips. The type of the chip can be
selected with the
flags argument in the config file.
Designation |
Resolution |
Input Channels |
flags |
MCP3001 |
10 bits |
1 |
0 |
MCP3002 |
10 bits |
2 |
1 |
MCP3004 |
10 bits |
4 |
2 |
MCP3008 |
10 bits |
8 |
3 |
MCP3201 |
12 bits |
1 |
4 |
MCP3202 |
12 bits |
2 |
5 |
MCP3204 |
12 bits |
4 |
6 |
MCP3208 |
12 bits |
8 |
7 |
MCP3301 |
13 bits |
1 |
8 |
MCP3302 |
13 bits |
4 |
9 |
MCP3304 |
13 bits |
8 |
10 |
SYSCTL VARIABLES
The following
sysctl(3) variables
are provided:
-
-
- hw.mcp3kadc0.vref
- Defines the reference voltage on the chip's
Vref
pin in millivolts (mV). It defaults to the
ADC's maximum output value + 1 in millivolts (e.g., 4096 for a 12-bit
ADC).
SEE ALSO
envsys(4),
spi(4),
sysctl(8)
HISTORY
The
mcp3kadc driver first appeared in
NetBSD
8.0.
AUTHORS
The
mcp3kadc driver was written by
Frank
Wille.