==== Pro Mini ====
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{{:boards:promini.jpg?200}}
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{{:boards:pro16m.jpg?200}}
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{{:boards:proasp.jpg?200}}
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Two examples of Pro Mini clones, one with an 8 Mhz XTAL and 3V3 VREG and the other with a 16 Mhz XTAL and 5V VREG. Both have an ATMEGA328P micro-controller.

=== Pinout ===
<code>
    DTR TXD RXD VCC GND GND
        PD1 PD0
TXD PD1                     RAW
RXD PD0                     GND
RST                         RST
GND                         VCC
2   PD2         PC5 A5  PC3  A3
3   PD3         PC4 A4  PC2  A2
4   PD4                 PC1  A1
5   PD5                 PC0  A0
6   PD6                 PB5  13 SCK
7   PD7  LED    RESET   PB4  12 MISO 
8   PB0  PB5    BUTTON  PB3  11 MOSI
9   PB1                 PB2  10
                PC6 PC7
            GND A6  A7
</code>
The above pinout is for the 3V3 example. The 5V example differs in that it places A5 and A4 alongside A6 and A7 at the bottom of the diagram.
=== Power ===
We can power the boards with VCC up to 5V or utilise the RAW input which will feed the regulator.

=== Communications ===
A [[:interfaces:cp2104|cp2104]] serial module is well suited to connect to the pro mini and is able to supply both 3V5 and 5V for VCC. The photos show a cp2104 module in the background.

=== Boot loader ===
An arduino boot loader is present on these devices which communicates at 57600 baud. This is a reliable speed for a Pro Mini with an 8MHz XTAL but 115200 baud can be used on the 16 MHz device if the  [[:tools:optiboot|Optiboot]] boot loader is installed.

In the arduino IDE, the 3V3 device is selected as an `Arduino Pro or Pro Mini (3.3V, 8 MHz) w/ ATMEGA328'.

=== ISP ===
The Pro Mini doesn't have an ISP connector but we can wire and
replace the boot loader, for example, with a [[interfaces:usbasp|USBasp]].

<code>
VDD
GND
RESET 
MISO  PB4
SCK   PB5
MOSI  PB3
</code>