Semiconductor device and data processing system selectively operating as one of a big endian or little endian system
The present invention is to provide a semiconductor device that can correctly switch endians on the outside even if the endian of a parallel interface is not recognized on the outside. The semiconductor device includes a switching circuit and a first register. The switching circuit switches between whether a parallel interface with the outside is to be used as a big endian or a little endian. A first register holds control data of the switching circuit. The switching circuit regards the parallel interface as the little endian when first predetermined control information, that is unchanged in the values of specific bit positions even if its high-order and low-order bit positions are transposed, is supplied to the first register, and regards the parallel interface as the big endian when second predetermined control information, that is unchanged in the values of specific bit positions even if its high-order and low-order bit positions are transposed, is supplied to the first register. Whatever the endian setting status, the control information can be correctly inputted without being influenced by the endian setting status.
1. A method for data processing in a display driving control device including an endian setting register, the method comprising:
operating the display driving control device to perform the steps of:
receiving an endian setting command;
storing the endian setting command in the endian setting register;
loading the endian setting command; and
after the loading, switching an operation mode based on a value of the endian setting command, the operation mode being switchable between a big endian mode and a little endian mode,
wherein the endian setting command comprises a high-order bit portion and a low-order bit portion, and
wherein the high-order bit portion and the low-order bit portion of the endian setting command are identical.
2. The method for data processing according to claim 1 , the display driving control device further comprising:
an interface circuit configured to receive the endian setting command; and
a data bus configured to transfer the endian setting command from the interface circuit to the endian setting register,
wherein the bit length of each of the high-order bit portion and the low-order bit portion is the same as the width of the data bus.
3. The method for data processing according to claim 2 , wherein the storing comprises:
when the big endian mode is selected, storing the high-order bit portion in the endian setting register and then storing the low-order bit portion in the endian setting register; and
when the little endian mode is selected, storing the low-order bit portion in the endian setting register and then storing the high-order bit portion in the endian setting register.
4. The method for data processing according to claim 1 , wherein the display driving control device is incorporated in a cellular phone.
5. A method for data processing in a display driving control device including an endian setting register, the method comprising:
operating the display driving control device to perform the steps of:
receiving an endian setting command and an endian setting address;
storing the endian setting command in the endian setting register corresponding to the endian setting address;
loading the endian setting command; and
after the loading, switching an operation mode based on a value of the endian setting command, the operation mode being switchable between a big endian mode and a little endian mode,
wherein the endian setting command comprises a high-order bit portion and a low-order bit portion,
wherein the endian setting address comprises a high-order bit portion and a low-order bit portion,
wherein the high-order bit portion and the low-order bit portion of the endian setting command are identical, and
wherein the high-order bit portion and the low-order bit portion of the endian setting address are identical.
6. The method for data processing according to claim 5 , the display driving control device further comprising:
an interface circuit configured to receive the endian setting command and the endian setting address; and
a data bus configured to transfer the endian setting command from the interface circuit to the endian setting register,
wherein the bit length of each of the high-order bit portion and the low-order bit portion of the endian setting command is the same as the width of the data bus of the data processor, and
wherein the bit length of each of the high-order bit portion and the low-order bit portion of the endian setting address is the same as the width of the data bus of the data processor.
7. The method for data processing according to claim 6 , wherein the storing comprises:
when the big endian mode is selected, storing the high-order bit portion in the endian setting register and then storing the low-order bit portion in the endian setting register; and
when the little endian mode is selected, storing the low-order bit portion in the endian setting register and then storing the high-order bit portion in the endian setting register.
8. The method for data processing according to claim 5 , wherein the display driving control device is incorporated in a cellular phone.