RM48L952: RM48L952

brendan johnson

Prodigy 140 points

Part Number: RM48L952
Other Parts Discussed in Thread: HALCOGEN

Dear sir / madam,

I am trying to obtain as much free GPIO as possible for a project, using the RM48x 337 BGA (ZWT)

Realistically I need ate least 116 GPIO pins.

I'm using the peripherals: 3-CAN, 1-I2C, and USB HOST and DEVICE.

The pins spare I am unsure of are External Memory Interface (EMIF) and the A2D pins.

Im guessing the EMIF could be used, however some of these pins are taken when configuring the RAM trace port (RTP) as GPIO.

The A2D im guessing cannot be used for GPIO?

Any ideas, is there a way of using the EMIF to get IO, i.e. could outputs be obtained by using data latch chips and chip selects/data lines form the micro?

Thanks

Brendan Johnson

over 8 years ago

0 QJ Wang over 8 years ago

TI__Guru**** 199106 points

Hello Brendan,

Some EMIF pins can be used as GPIO. RTP and EMIF are multiplexed on those pins:
1. Check "RTP" in pinmux page of HAlCoGen, so those muxed pins are used for RTP instead of EMIF
2. Configure RTP pins as GIO pins: RTP pin control registers (RTPPC[8:0])

0 Chuck Davenport over 8 years ago

TI__Guru 59540 points

Hi Brendan,

Also consider that the A2D pins can be used to detect the voltage levels and translated into either 1 or 0 by software in case of inputs that do not change frequently.

0 brendan johnson over 8 years ago in reply to Chuck Davenport

Prodigy 140 points

Many thanks Chuck/QJ.

Brendan

0 brendan johnson over 8 years ago in reply to brendan johnson

Prodigy 140 points

I've written a quick piece of software as below to read from the EMIF_DATA pins [0] to [15].

volatile uint16_t ext_mem_iface_data;
volatile uint16_t *ext_mem_iface_ptr;

ext_mem_iface_ptr = (volatile uint16_t *)0x64000000;
ext_mem_iface_data = *ext_mem_iface_ptr;

The memory read uses CS2 which I don't intend to connect.
Also the data pins EMIF_DATA[0] to [15] are not being used by anything else.
RTP will be configured as GEN IO and thus will use the EMIF_ADDR[6] to [21].

It seems to work ok, however I realize I might be "glitching" the EMIF_ADDR pins for the short duration of the read.
What do you think, If I can get away with it I can use it for 16 more inputs, but NOT safety critical?
Or do you think it's a bit risky?

Many thanks

Brendan

0 QJ Wang over 8 years ago in reply to brendan johnson

TI__Guru**** 199106 points

Hello Brendan,

Very smart. It should work without any problem. Thanks

0 brendan johnson over 8 years ago in reply to QJ Wang

Prodigy 140 points

fantastic, many thanks, I owe you one.

Brendan

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RM48L952: RM48L952