Memory control device, mobile terminal, and computer-readable recording medium

1. A memory control device that performs (a) a write-in operation for writing, to a frame memory, data transferred from a host and (b) a read-out operation for reading the data written in the frame memory and then transferring this data to display control circuitry, the memory control device comprising:

write-in start position control circuitry that performs a process of shifting, by a given shifting amount, a start position of the write-in operation to the frame memory, the given shifting amount being predetermined so as not to exceed a capacity reserved in advance in the frame memory in a case where (i) a read-out period from a start to an end of the read-out operation is different in length from a write-in period from a start to an end of the write-in operation and (ii) the write-in operation is started; wherein

the frame memory is a single memory which stores image data corresponding to one frame, and

the frame memory has a storage capacity that is extended by at least the shifting amount beyond a storage capacity for 1 frame of the data.

2. The memory control device as set forth in claim 1 , further comprising:

determination circuitry that at least determines whether or not a time point of the start of the write-in operation is in the shifting period predetermined in accordance with either a difference between the read-out period and the write-in period or a period of a sum of a vertical synchronization signal pulse period and a vertical back porch period in the read-out operation,

the process of shifting the start position of the write-in operation being performed in a case where the determination circuitry has determined that the time point of the start of the write-in operation is in the shifting period.

3. The memory control device as set forth in claim 2 , wherein:

in a case where a speed of the read-out operation is faster than a speed of the write-in operation, the shifting period is set to the period of the sum.

4. The memory control device as set forth in claim 2 , wherein:

in a case where a speed of the write-in operation is faster than a speed of the read-out operation, the shifting period is set to the period from a time point of the start of the read-out operation to a time point obtained by going back by a length of the write-in period from a time point of the end of the read-out operation.

5. The memory control device as set forth in claim 2 , wherein:

the shifting amount is predetermined in accordance with the period of the sum, the read-out period and the write-in period.

6. The memory control device as set forth in claim 2 , wherein:

the shifting amount is predetermined in accordance with a product of a length of the period of the sum and a ratio of a length of the read-out period to a length of the write-in period.

7. The memory control device as set forth in claim 1 , wherein:

the storage capacity of the frame memory is at least smaller than a storage capacity for 2 frames of the data.

8. The memory control device as set forth in claim 1 , further comprising:

read-out start position control circuitry that causes the read-out operation to start at a position that is the same as the start position of the write-in operation, which start position is shifted by the shifting amount in the frame memory, in a case where the write-in start position control circuitry performs the process of shifting, by the given shifting amount, the start position of the write-in operation to the frame memory.

9. A mobile terminal comprising the memory control device as set forth in claim 1 .

10. A non-transitory computer-readable storage medium where a memory control program for causing a computer as function of the memory control device as set forth in claim 1 is stored.