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STM32 GPIO Speed
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Why do we need to set speed for GPIO output pins in STM32?
The STM32F4 Reference Manual on page 278 says that:
The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle.
Then why do we need to set speed to the pins while it is specified?.
stm32
asked 3 hours ago
Amin
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up vote
2
down vote
favorite
Why do we need to set speed for GPIO output pins in STM32?
The STM32F4 Reference Manual on page 278 says that:
The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle.
Then why do we need to set speed to the pins while it is specified?.
stm32
asked 3 hours ago
Amin
155
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to EE.SE.
– Sparky256
2 hours ago
Hello Amin! Please see this related question.
– bitsmack
9 mins ago
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Why do we need to set speed for GPIO output pins in STM32?
The STM32F4 Reference Manual on page 278 says that:
The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle.
Then why do we need to set speed to the pins while it is specified?.
stm32
asked 3 hours ago
Amin
155
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Why do we need to set speed for GPIO output pins in STM32?
The STM32F4 Reference Manual on page 278 says that:
The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle.
Then why do we need to set speed to the pins while it is specified?.
stm32
stm32
asked 3 hours ago
Amin
155
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
Amin
155
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 1 hour ago
asked 3 hours ago
Amin
155
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
Amin
155
asked 3 hours ago
Amin
155
155
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Amin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Welcome to EE.SE.
– Sparky256
2 hours ago
Hello Amin! Please see this related question.
– bitsmack
9 mins ago
add a comment |Â
Welcome to EE.SE.
– Sparky256
2 hours ago
Hello Amin! Please see this related question.
– bitsmack
9 mins ago
Welcome to EE.SE.
– Sparky256
2 hours ago
Welcome to EE.SE.
– Sparky256
2 hours ago
Hello Amin! Please see this related question.
– bitsmack
9 mins ago
Hello Amin! Please see this related question.
– bitsmack
9 mins ago
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
3
down vote
accepted
STM32F4-Refrence Manual in page 278 says that "The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle"
This text is referring to input pins, not outputs.
The speed setting only affects pins used as outputs. It controls the slew rate (drive strength) on outputs. Using an excessively high speed may cause ringing and EMI on outputs, so it is important to use the minimum speed required for your application.
answered 2 hours ago
duskwuff
15.8k32546
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
add a comment |Â
up vote
1
down vote
Most any very fast CPU or MPU have bus or GPIO pin speeds that require 10 ohm to 27 ohm resistors in series at the endpoint of the trace to prevent ringing and adjacent trace cross talk. If your GPIO data or IO control is erratic then maybe you have to slow down AHB1 rate or insert those resistors I mentioned.
If pin is an input then resistor is at the pin. If the pin is an output then resistors is at the device pin being driven. Dampening or impedance matching resistors might allow you to keep current AHB1 speed. If you still have data corruption then you MUST slow down the AHB1 rate.
answered 2 hours ago
Sparky256
10.3k21534
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
STM32F4-Refrence Manual in page 278 says that "The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle"
This text is referring to input pins, not outputs.
The speed setting only affects pins used as outputs. It controls the slew rate (drive strength) on outputs. Using an excessively high speed may cause ringing and EMI on outputs, so it is important to use the minimum speed required for your application.
answered 2 hours ago
duskwuff
15.8k32546
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
add a comment |Â
up vote
3
down vote
accepted
STM32F4-Refrence Manual in page 278 says that "The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle"
This text is referring to input pins, not outputs.
The speed setting only affects pins used as outputs. It controls the slew rate (drive strength) on outputs. Using an excessively high speed may cause ringing and EMI on outputs, so it is important to use the minimum speed required for your application.
answered 2 hours ago
duskwuff
15.8k32546
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
add a comment |Â
up vote
3
down vote
accepted
up vote
3
down vote
accepted
STM32F4-Refrence Manual in page 278 says that "The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle"
This text is referring to input pins, not outputs.
The speed setting only affects pins used as outputs. It controls the slew rate (drive strength) on outputs. Using an excessively high speed may cause ringing and EMI on outputs, so it is important to use the minimum speed required for your application.
answered 2 hours ago
duskwuff
15.8k32546
STM32F4-Refrence Manual in page 278 says that "The data present on the I/O pin are sampled into the input data register every AHB1 clock cycle"
This text is referring to input pins, not outputs.
The speed setting only affects pins used as outputs. It controls the slew rate (drive strength) on outputs. Using an excessively high speed may cause ringing and EMI on outputs, so it is important to use the minimum speed required for your application.
answered 2 hours ago
duskwuff
15.8k32546
answered 2 hours ago
duskwuff
15.8k32546
answered 2 hours ago
duskwuff
15.8k32546
answered 2 hours ago
duskwuff
15.8k32546
15.8k32546
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
add a comment |Â
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
Inputs as well. It is guaranteed that the change of the input pin by the external world will propagate as quiche as the bus speed.
– P__J__
17 mins ago
add a comment |Â
up vote
1
down vote
Most any very fast CPU or MPU have bus or GPIO pin speeds that require 10 ohm to 27 ohm resistors in series at the endpoint of the trace to prevent ringing and adjacent trace cross talk. If your GPIO data or IO control is erratic then maybe you have to slow down AHB1 rate or insert those resistors I mentioned.
If pin is an input then resistor is at the pin. If the pin is an output then resistors is at the device pin being driven. Dampening or impedance matching resistors might allow you to keep current AHB1 speed. If you still have data corruption then you MUST slow down the AHB1 rate.
answered 2 hours ago
Sparky256
10.3k21534
add a comment |Â
up vote
1
down vote
Most any very fast CPU or MPU have bus or GPIO pin speeds that require 10 ohm to 27 ohm resistors in series at the endpoint of the trace to prevent ringing and adjacent trace cross talk. If your GPIO data or IO control is erratic then maybe you have to slow down AHB1 rate or insert those resistors I mentioned.
If pin is an input then resistor is at the pin. If the pin is an output then resistors is at the device pin being driven. Dampening or impedance matching resistors might allow you to keep current AHB1 speed. If you still have data corruption then you MUST slow down the AHB1 rate.
answered 2 hours ago
Sparky256
10.3k21534
add a comment |Â
up vote
1
down vote
up vote
1
down vote
Most any very fast CPU or MPU have bus or GPIO pin speeds that require 10 ohm to 27 ohm resistors in series at the endpoint of the trace to prevent ringing and adjacent trace cross talk. If your GPIO data or IO control is erratic then maybe you have to slow down AHB1 rate or insert those resistors I mentioned.
If pin is an input then resistor is at the pin. If the pin is an output then resistors is at the device pin being driven. Dampening or impedance matching resistors might allow you to keep current AHB1 speed. If you still have data corruption then you MUST slow down the AHB1 rate.
answered 2 hours ago
Sparky256
10.3k21534
Most any very fast CPU or MPU have bus or GPIO pin speeds that require 10 ohm to 27 ohm resistors in series at the endpoint of the trace to prevent ringing and adjacent trace cross talk. If your GPIO data or IO control is erratic then maybe you have to slow down AHB1 rate or insert those resistors I mentioned.
If pin is an input then resistor is at the pin. If the pin is an output then resistors is at the device pin being driven. Dampening or impedance matching resistors might allow you to keep current AHB1 speed. If you still have data corruption then you MUST slow down the AHB1 rate.
answered 2 hours ago
Sparky256
10.3k21534
edited 26 mins ago
answered 2 hours ago
Sparky256
10.3k21534
answered 2 hours ago
Sparky256
10.3k21534
answered 2 hours ago
Sparky256
10.3k21534
10.3k21534
add a comment |Â
add a comment |Â
Amin is a new contributor. Be nice, and check out our Code of Conduct.
Amin is a new contributor. Be nice, and check out our Code of Conduct.
Amin is a new contributor. Be nice, and check out our Code of Conduct.
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Welcome to EE.SE.
– Sparky256
2 hours ago
Hello Amin! Please see this related question.
– bitsmack
9 mins ago