4D systems Picaso, Datasheet, Page: 10 / 28

Picaso Processor Datasheet
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2017 4D Labs Semiconductors Page 10 of 27
www.4dsystems.com.au
RD pin (Display Read):
This is the display read strobe signal. The Picaso
asserts this signal LOW when reading data from the
display in conjunction with the display data bus (D0-
D15). Connect this pin to the Read (RD) signal of the
display.
Item Sym Min Typ Max
Read Low Pulse tRL 150 - -
Read High Pulse tRH 150 - -
Read Bus Cycle Total tRT 300 - -
Read Data Hold tDH 75 - -
5.2. SPI Interface – Memory Card
The Picaso supports SD, micro-SD and MMC memory
cards via its hardware SPI interface. The memory card
is used for all multimedia file retrieval such as images,
animations and movie clips and the SPI interface is
dedicated for this purpose only. The memory card can
also be used as general purpose storage for data
logging applications (RAW and FAT16 format support).
Support is available for micro-SD with up to 2GB
capacity and for high capacity HC memory cards
starting from 4GB and above.
SDI pin (SPI Serial Data In):
The SPI Serial Data Input (SDI). SD memory card use
only. Connect this pin to the SPI Serial Data Out (SDO)
signal of the memory card.
SDO pin (SPI Serial Data Out):
The SPI Serial Data Output (SDI). SD memory card use
only. Connect this pin to the SPI Serial Data In (SDI)
signal of the memory card.
SCK pin (SPI Serial Clock):
The SPI Serial Clock output (SCK). SD memory card use
only. Connect this pin to the SPI Serial Clock (SCK)
signal of the memory card.
SDCS pin (SD Memory Card Chip Select):
SD Memory-Card Chip Select (SDCS). SD memory card
use only. Connect this pin to the Chip Enable (CS)
signal of the memory card.
5.3. Serial Ports – UARTS
The Picaso Processor has two dedicated hardware
Asynchronous Serial ports that can communicate with
external serial devices. These are referred to as the
COM0 and the COM1 serial ports.
The primary features are:

Full-Duplex 8 bit data transmission and reception.

Data format: 8 bits, No Parity, 1 Stop bit.

Independent Baud rates from 300 baud up to
256K baud.

Single byte transmits and receives or a fully
buffered service. The buffered service feature
runs in the background capturing and buffering
serial data without the user application having to
constantly poll any of the serial ports. This frees
up the application to service other tasks.