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MCP3KADC(4) FreeBSD Kernel Interfaces Manual MCP3KADC(4) 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. FreeBSD 14.1-RELEASE-p8 August 18, 2015 FreeBSD 14.1-RELEASE-p8