2
\$\begingroup\$

Title itself is explanatory. Also tell me what are the things I should take care of when I connect other IC's to it? With AVR's I never had to deal with these things. But now when dealing with ARM MCU's I think I have to consider these stuffs.

I will rephrase the question. Tell me, is it safe to connect LPC MCU to other common IC's like an AVR or L293D diver IC or 74xx series IC's etc without any interfacing circuits?

\$\endgroup\$
0

4 Answers 4

Reset to default
4
\$\begingroup\$

The LPC1xxx family has 3.3V IO but it is 5V tolerant. This means that it will only give 3.3V when you output '1' but it will tolerate up to 5V when the pin is configured as an input. Many other 3.3V MCUs/logic chips are not so convenient.

What this means in practice is that you can connect to almost any standard 5V logic chip. You lose a a bit of noise resistance but I never found this to be a problem.

The thing to remember is that you will need two supplies: one 3.3V for the LPC1xxx and another 5V one if you wish to use some 5V chips. You cannot run the LPC1xxx from 5V! (but you can use just a simple low drop-out regulator to get from 5V you have to 3.3V you need)

\$\endgroup\$
1
  • 3
    \$\begingroup\$ Microchip has an appnote about interfacing 3V and 5V systems. \$\endgroup\$
    – stevenvh
    Jun 13, 2011 at 13:48
5
\$\begingroup\$

The digital interface pins are defined as:

  • logic low output as maximum \$0.4V\$, and logic high output as minimum \$V_{DD} - 0.4V\$
  • logic low input as maximum \$0.3 \times V_{DD}\$, and logic high input as maximum \$0.7 \times V_{DD}\$

At a glance, the voltage levels appear similar to LVCMOS.

\$\endgroup\$
2
  • \$\begingroup\$ I found something like LVC on the NXP's site. I have never heard of it. Maybe it is related to LVCMOS. \$\endgroup\$
    – 0xakhil
    May 24, 2011 at 14:57
  • 2
    \$\begingroup\$ @oxakhil - NXP LVC is LVCMOS. \$\endgroup\$
    – stevenvh
    Jun 13, 2011 at 15:11
3
\$\begingroup\$

The LPC1114 is a Cortex-M0 controller. Cortex (ARMv7, not to be confused with ARM7) is the latest generation of 32-bit ARM controllers.

I'm not sure what you're thinking of when you say "connect other ICs to it". The main thing to consider is the voltage the peripherals need/supply, which should match the controller's \$V_{DD}\$, 3.3V typical according to the datasheet.

\$\endgroup\$
3
  • 1
    \$\begingroup\$ Agreed, avr, arm, pic, doesnt matter you always have to do your system engineering and read data sheets and connect things properly. \$\endgroup\$
    – old_timer
    May 24, 2011 at 13:52
  • \$\begingroup\$ @dwelch that was helpful. \$\endgroup\$
    – 0xakhil
    May 24, 2011 at 14:31
  • \$\begingroup\$ I was just expanding on what stevenvh had said \$\endgroup\$
    – old_timer
    May 24, 2011 at 17:28
3
\$\begingroup\$

First half of your question:

Stevenvh is close, the NXP 1114 is a Cortex-M0 that is a class ARMv6-M based MCU.

Both the Cortex-M0 and Cortex-M1 is based on ARMv6-M. (The Cortex-M3 is based on ARMv7-M).

Please note that in the ARM Cortex world the M more or less stands for a core that fits well in a MCU. (Then there is the R and A series for Application and more hardtime Real time demands).

The Cortex-M is a replacement for ARM7 that was based on ARMv4 or ARMv5, and the Cortex-A is kind of a replacement for ARM9 and ARM11.

But this answer is very academic, just remember that ARM7 and ARMv7 is not the same thing. One is a type of MCU and the other is the core inside a MCU...

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.