protocol in the micro-controller. There are
four
UART modules from
UART3
to
UART0
in ATmega2560. The TX and RX pins of
UART3:1
are present on this header. The TX and
RX pins of
UART0
is not made available on the board. Apart from using these pins as TX
and RX pins of UART module, they also have certain alternative functions, the details of
the same is shown in Figure
. This header also has two pins of VCC i.e. 5V and GND
each.
2.1.13 SPI header
This header is a group of pins of ATmega2560 that can be used as Bus pins for
Serial
Peripheral Interface (SPI)
protocol in the micro-controller. The
MISO
or
PB3
are two
names of the same pin of micro-controller. Similarly,
MOSI
or
PB2
and
SCK
or
PB1
are
two names of the same pin of micro-controller. The other name for the
Slave Select
pin
SS0
is
PB2
. There is only one Slave Select pin available in ATmega2560, but for interfac-
ing multiple devices via SPI protocol, one can configure any GPIO pin as Slave Select.
We have provided one such GPIO pin
PJ7
and named it as
SS1
. Apart from using these
pins as Bus pins of SPI, they also have certain alternative functions, the details of the
same is shown in Figure
. This header also has two pins of VCC i.e. 5V and GND each.
2.1.14 PWM header
This header is a group of pins of ATmega2560 that can be used as
Output Compare
or
Pulse Width Modulation (PWM)
pins for the Timers in the micro-controller. There
are
two 8-bit
Timers,
Timer 0
and
2
and
four 16-bit
Timers,
Timer 1
,
3
,
4
and
5
in AT-
mega2560.
8-bit
Timers have
two
PWM Channels named as
OCnA
and
OCnB
where
n
stands for Timer number and will be of value
0
and
2
.
16-bit
Timers have
four
PWM
Channels named as
OCnA
,
OCnB
and
OCnC
where
n
stands for Timer number and will
be of value
1
,
3
,
4
and
5
. Total
14
PWM Channels available on this header, they are:
OC0A
,
OC0B
,
OC1A
,
OC1B
,
OC1C
,
OC2A
,
OC2B
,
OC3A
,
OC4A
,
OC4B
,
OC4C
,
OC5A
,
OC5B
and
OC5C
. The PWM channel
OC0A
and
OC1C
are two names of the same pin of
micro-controller. The PWM channels
OC3B
and
OC3C
are not present on this header,
since they have other alternate functions which are given more priority. These chan-
nels
OC0A
and
OC1C
can be found in Figure
. The
x
in the header name
OCn(A/B/C)
stands for Timer number and ranges from
5
to
0
. Apart from using these pins as Output
Compare or PWM channel, they also have certain alternative functions, the details of
the same is shown in Figure
. This header also has two pins of VCC i.e. 5V and GND
each. Also, the
RESET
pin of ATmega2560 is available on this header.
2.1.15 ESP32 GPIO header
This is divided into
two
headers, each of
2 x 4
pins header. These are the pins of ESP32
and are named with their default functionality of GPIO. Apart from using these pins as
GPIO, they also have certain alternative functions, the details of the same is shown in
16
