CY7C68053

Document # 001-06120 Rev *J

Page 10 of 42

3.14.1 Three Control OUT Signals

The 56-pin package brings out three of these signals,

CTL0–CTL2. The 8051 programs the GPIF unit to define the CTL

waveforms. CTLx waveform edges can be programmed to make

transitions as fast as once per clock cycle (20.8 ns using a

48 MHz clock).

3.14.2 Two Ready IN Signals

The FX2LP18 package brings out all two Ready inputs

(RDY0–RDY1). The 8051 programs the GPIF unit to test the

RDY pins for GPIF branching.

3.14.3 Long Transfer Mode

In master mode, the 8051 appropriately sets GPIF transaction

count registers (GPIFTCB3, GPIFTCB2, GPIFTCB1, or

The GPIF automatically throttles data flow to prevent under or

overflow until the full number of requested transactions

complete. The GPIF decrements the value in these registers to

represent the current status of the transaction.

3.15 ECC Generation[6]

The MoBL-USB can calculate Error Correcting Codes (ECCs) on

data that passes across its GPIF or Slave FIFO interfaces. There

are two ECC configurations: two ECCs, each calculated over

256 bytes (SmartMedia Standard) and one ECC calculated over

512 bytes.

The ECC can correct any 1-bit error or detect any 2-bit error.

3.15.1 ECC Implementation

The two ECC configurations are selected by the ECCM bit.

3.15.1.1 ECCM = 0

Two 3-byte ECCs are each calculated over a 256-byte block of

data. This configuration conforms to the SmartMedia Standard.

This configuration writes any value to ECCRESET, then passes

data across the GPIF or Slave FIFO interface. The ECC for the

first 256 bytes of data is calculated and stored in ECC1. The ECC

for the next 256 bytes is stored in ECC2. After the second ECC

is calculated, the values in the ECCx registers do not change

until ECCRESET is written again, even if more data is

subsequently passed across the interface.

3.15.1.2 ECCM = 1

One 3-byte ECC is calculated over a 512-byte block of data.

This configuration writes any value to ECCRESET then passes

data across the GPIF or Slave FIFO interface. The ECC for the

first 512 bytes of data is calculated and stored in ECC1; ECC2

is unused. After the ECC is calculated, the value in ECC1 does

not change until ECCRESET is written again, even if more data

is subsequently passed across the interface.

3.16 USB Uploads and Downloads

The core has the ability to directly edit the data contents of the

internal 16-kByte RAM and of the internal 512-byte scratch pad

RAM using a vendor-specific command. This capability is

normally used when ‘soft’ downloading user code and is

available only to and from internal RAM, only when the 8051 is

held in reset. The available RAM spaces are 16 kBytes from

0x0000–0x3FFF (code/data) and 512 bytes from

0xE000–0xE1FF (scratch pad data RAM).[7]

3.17 Autopointer Access

FX2LP18 provides two identical autopointers. They are similar to

the internal 8051 data pointers, but with an additional feature:

they can optionally increment after every memory access. The

autopointers are available in external FX2LP18 registers, under

control of a mode bit (AUTOPTRSET-UP.0). Using the external

FX2LP18 autopointer access (at 0xE67B – 0xE67C) allows the

autopointer to access all RAM. Also, the autopointers can point

to any FX2LP18 register or endpoint buffer space.

controllers. One controller automatically operates at boot time to

load the VID/PID/DID, configuration byte, and firmware. The

second controller is used by the 8051, once running, to control

resistors even if no EEPROM is connected to the FX2LP18. The

value of the pull up resistors required may vary, depending on

The pull up resistors used must be such that when the EEPROM

FX2LP18. For example, if the EEPROM runs off a 3.3 V supply

ohm

. This requirement may also vary depending on the devices

details.

External EEPROM device address pins must be configured

properly. See Table 6 on page 11 for configuring the device

address pins.

is required by an external processor. This is because the

FX2LP18 comes out of reset with the DISCON bit set, so the

device will not enumerate without an EEPROM (C2 load) or

EEPROM emulation.

Notes

6. To use the ECC logic, the GPIF or Slave FIFO interface must be configured for byte-wide operation.

7. After the data is downloaded from the host, a ‘loader’ can execute from internal RAM in order to transfer downloaded data to external memory.

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