How do you program arm processors?

JTAG

NXP has a serial protocol, and USB mass-storage (simulated filesystem).
No need for JTAG.

STLink, LPCLink, JLink, BlackMagicProbe,...
there are plenty of programmers. And for SWD/JTAG, there is no 
distinction between programmers and debug probes.

With a programmer...

Jayesh S. wrote:
> But when it comes to ARM, i havent
> found anything on what you need to program / how to program arm chips.

Some chips have a builtin boot-loader: You only need a COM port, for 
example a USB-to-serial device like ftdi or other brand. Cheap solution, 
somewhat slower than SWD due to the slower bitrate of a COM port.

So, in detail:

- The LPC from NXP, programmable with 'FlashMagic'. Use google, 
FlashMagic is free downloadable and usable.

-  The STM32Fxxx, programmable with: my own 'STM32Prog', downloadable on 
www.mikrocontroller.net, subforum 'projekte&code', also with old 'erfos' 
programmer, also with a piece of software from ST somewhat like 
'bootloader demonstrator' or so.

- The chips from Nuvoton are somewhat special: they provide on the chip 
a flash-area of 4K bytes or so (called LDROM), which is outside of the 
common flash. In this LDROM you can install a bootloader of your own. 
Nuvoton provides ready made bootloaders, but I do not know, if they 
are pre-programmed in the chips on delivery.

Usually ALL modern Cortex chips are programmable with a suitable 
JTAG/SWD programming dongle, as there are: Segger's J-Link (VERY 
expensive!), Segger's J-Link-edu (expensive) and China-clones of them 
(not expensive, but...)
The original Segger parts also program older ARM devices, which have no 
SWD, but JTAG

The Chip-manufacturers (NXP, Nuvoton, ST) use to provide also dongles 
like ST-Link, Nu-Link etc. - but this devices usually do the job only 
with chips from the particular company.

Finally: using chips with bootloader you only need a cheap standard 
electronics like a USB to Serial converter, the programming algorithm is 
published and there are at least some independent programming Apps to do 
the job. With JTAG/SWD you need special electronics, the programming 
algorithms are usually not published by the manufacturers and the good 
programmers are expensive or even VERY expensive.

That's it.

W.S.